I'm new to WOW and I just got the starter edition which allows you to play up to lvl 20 and other smaller restrictions. I want to know how much can I really play with these restrictions? Can I still go pretty far into the game as a lvl 20?
The short answer is no. The game has a level cap of 100 (assuming you have all expansions), so you'd get 20% of the total leveling experience and none of the post-game (what you do when you hit level cap) content.
The starter pack is roughly analogous to a demo in a singleplayer game in that regard; it gives you enough of the game to understand whether or not it's something you'd want to spend money on.
The long answer...
You can sink a lot of time into a level 20 character, even with the restrictions imposed upon a starter edition account. One of the most common ways to do this is in PvP battlegrounds.
For some people (including myself), the fun in this is finding ways to explore the world or optimize your character within the starter edition restrictions. You can still do the following in the starter edition:
- Level professions up to rank 100
- Run level 10-20 dungeons solo, or with up to 5 people (although there are only a few, so these can quickly get boring).
- Complete all quests available to your faction from level 1-20
- Collect companions and toys (obviously, a lot of these are not available to a level 20, but there are still loads to collect).
- Participate in yearly world events like Brewfest(Oktoberfest), Midsummer Fire Festival(Summer Solstice), and Hallow's End(Halloween). While not all content will be available for a level 20, there is almost always something to do for everyone.
- Visit the Darkmoon Faire. The carnival comes to town for the first week of every month. There are quests, gear, and toys exclusive to this event.
- Explore! There are very few barriers in the game that will not allow you to enter due to not having the latest expansion. The only risk in traveling is that most areas are dangerous to a low-level player (but don't let that stop you).
- PvP Battlegrounds: Once you hit level 20, you are matchmade against allies and opponents levels 20-24, but all players levels are scaled to 24 to compensate for hit chance/base stat disadvantages. You can use online databases like http://www.wowhead.com/ to find the best gear for a level 20 character. Cynwise has created a great guide, albeit outdated, for level 20 twinking https://greentintedgoggles.wordpress.com/2011/07/26/a-guide-to-trial-account-twinking/.
If you're up for a big time sink, and a bit of a challenge, you can play WoW for quite a while at level 20. And if you're getting a little bored, you can always start over from level 1 with a new class!
One of my level 20 characters, in case you are interested: http://us.battle.net/wow/en/character/Auchindoun/Creativity/simple
Expansion on the Darkmoon Faire (DMF): This event occurs at the beginning of every month and lasts a week. There is a buff the merry go round gives called "Whee!" Which lasts up to 60 minutes or death, this provides a 10% leveling experience buff and 10% reputation buff. I recommend getting reapplication as needed.
-Obtain the intro quest in any city available at level 10. This rewards 5 tickets. Use one ticket to buy darkmoon storage box (16 slot bag) at the faire (same guy as quest turn in).
-Go back to the DMF at level 15, fish up 100 darkmoon daggermaw (careful not to open bloated sharks as you will loot more than the 10g cap-open them for after you subscribe and the gold cap is lifted).
-Purchase the "faded treasure map" from the female blood elf locate on the pier, complete the quest, receive 100 ticket reward, buy heirloom gear.
-The DMF has a vendor who sells 29 different heirlooms. It takes 18 level 15-20 characters completing the faded treasure map quest to buy all of them.
Battleground Bonus Event (BBE): -During the BBE you can gain 300 honor for each character's first win of each day. Hunters and discipline priests are overpowered at this level range. Buy more heirlooms with honor (I think up to 12-15 via honor).
Level 1 mount: -Once you have 35+ heirlooms, you will receive the "heirloom hoarder" achievement (I personally have obtained this on a starter account). This rewards a level one motorcycle mount. It is auto learned and in your mount tab upon earning it. You may use this mount at level one!
Reputation 16 slot bags: -You can buy tabards from race/faction vendors in each major city. They are located near each city's flight path. Equipping a tabard while in a dungeon will reward a specific reputation (open this window my pressing "u"). At revered, you can buy/equip only one of each rep bag ~1g70s each. There are a total of 6 bags you can unlock/obtain this way.
Gold -If you find yourself repeatedly capping at 10g (and you will), you can spend down by buying vendor 10-12 slot bags, rep bags, bank slots, reputation mounts, pets, toys, and possibly stackable reagents with a close buy/vendor price to help preserve gold once you subscribe-then vendor items after sub.
Macros -Macros can be useful but are not required for successful gameplay. Type /macro to open the window. I mostly use macros for healing spells or utility spells such as: /cast [@mouseover, exists] spell; same spell This allows you cast on another player my only placing your mouse curser over the player and pressing the keybind on your keyboard. /castsequence reset=7 spell, another spell, yet another spell This allows you to tie many different spells together. Mostly used for attack spells.
There are many other useful macros out there which I will not list.
If/when you subscribe: One could easily play 1-3 months with the information mentioned above. If/when you subscribe, you may have played all of the available class combinations which should give you a better feel for the game.
For newcomers, I would suggest playing damage specialization (DPS) and hold off on tanking or healing specializations since they are more critical in dungeons and to a lesser extent battlegrounds. Other players will expect you to know what you are doing if you play a tank/heal role. As a DPS people will not pay as much critical attention to you, which give more time to learn and enjoy the game.
Good luck and have fun! Austintexas/Dalaran