If money is an issue, I will reccomend 3 games that have given me the most longevity.
1. World of Warcraft (They have a sale on now, 5 US dollars for each expansion.)
*Online* MMORPG
OK after the free time is up you will need to subscribe, but for 15 US Dollars a month you will not find any better entertainment.
The game will keep you going longer than possibly any other game on the market, and personally as someone who used to spend hundreds of dollars a month on games, this has seriously cut down on my outgoings.
2. Football Manager 2011
Strategy Simulation
Argentinians have a long and proud football history, If you like football at all, then this should be your game of choice as a simulation.
I log weeks of game time on this game every year, and this franchise has been undoubtedly the market leader since it's original launch as Championship manager in 1992)
3. Fallout 3
Action/Rpg
Offline, immersive, so much on offer here.
Budget options:-
I'm a retro gaming fan, I play on a lot of emulators.
There is a huge back catalog of older titles that are now public domain.
Google is your friend.
Ebay is always an option, you can often buy PC games for pennies.
A good game never stops being good.
I still play classics like Icewind dale despite it being 10 years old, I recently picked up a compliation containing IWD 1+2 Fallout 1+2 and Planescape Torment for 10 dollars, and if you havent heard of or played any of the above, then shame on you. (Fallout 2 was tedious)
Finally, on the subject of online roleplaying games.
If those are your thing, Due to the dominance of World of Warcraft, games like Lord of the Rings online or Dungeons and Dragons online are now totally FREE download and play.
No catch!