Oblivion GOTY $6.24: http://store.steampowered.com/app/900883/?snr=1_7_7_204_150_…
Morrowind $5: http://store.steampowered.com/app/22320/?snr=1_7_7_204_150_1
(I have been downloading quite a few Morrowind mods for a playthrough)
Skyrim (unfortunately only 50% off) $17.50: http://store.steampowered.com/app/72850/?snr=1_7_7_204_150_1
Dragonborn Legendary Edition $30: http://store.steampowered.com/sub/28187/?snr=1_5_9__403
Just a warning, these games are incredible time consuming if you want to do all the quests and explore the entire world, decorate homes, do extra mod related quests, etc. My Oblivion save game was about 200 hours long. And make sure you put the games on SSDs since there are frequent crashes and the game initially takes a long time to load, especially if you have lots of hires 2K texture replacers. But $6 for a 200 hour game is great value for a retiree or someone on disability or unemployment. All you need is an internet connection to grab mods, to DL the game via Steam, and Steam's DRM.
I know there is a pirated version of Skyrim, but I think it best to go legit since I am not sure SKSE (a prerequisite for some mods) works with altered executables.
Here's a huge sorted Morrowind mods list, but some links may be dead: http://www.mwmythicmods.com/telesphoros.htm
If you don't want to spend days downloading mods, unpacking and tweaking load orders, just get the Morrowind Overhaul package 1.7 GB) at this AU mirror: http://www.ausgamers.com/files/details/html/69080
For a hardcore Oblivion experience, try FCom, which combines several overhauls: http://devnull.sweetdanger.net/convergence.html . There's also some non-FCom mods mentioned on that site: http://devnull.sweetdanger.net/ It's a little complex, but if complexity daunts you, stay with console games. The ability to tweak, customize & 'hack", to roll your own OS, is what I love about PCs.
There's an all in one FCom package here to save time: http://www.superpackden.mastertopforum.net/download-installa…
A Download link is: https://docs.google.com/file/d/0B_pHj0dQg6a6azhsNUtaMG1MR2s/…
An alternative to FCOM is Oblivion War Cry - New Dimension ( http://thewormproductions.blogspot.com.au/2011/09/oblivion-w… ) Warning, even recompressed with Freearc it is 2.7GB on my HDD, or 8.7 GB unpacked!
A third alternative is WAC, Waalx Animals & Creatures, 550 MB: http://tesalliance.org/forums/index.php?/files/file/1318-wac…
Hav fun.
Dragonporn??.. Ahahaha..