As others have mentioned above, KotOR is available on Steam for not very much and is frequently offered on sale. It is a brilliant game with a brilliant BioWare story. KotORII is a much better game but at release suffered from many bugs, half-cut content and the ending (as others have described) is quite abrupt. Still, 2 took the good stuff from 1 and made them better. The customisation, choice making, gear/crystals, weapons, jedi abilities and skills, etc, etc.
Despite the faults, I've replayed it several times and will again several more in time I'm sure. The role playing, the combat and gameplay are superb. BioWare forgot that it can be fun to gear up the team with all the cool armours and weapons available when they made ME2 (or even JE for that matter!). They story is equally epic and it's truly a gaming tragedy that Lucasarts forced Obsidian to release it when they did. What was the damned hurry? So it doesn't make a release window, so what? Better to release it months or a year later and release a much better, finished, polished product. I don't know why Obsidian got their reputation when it's Lucasarts' fault.
Some fans formed a group called Team Gizka and were determined to restore as much of the cut content and fix bugs as they could. It promised a lot and ultimately KotORII would become as close to what it coulda/shoulda/woulda been had they more time originally. TSL Restoration Project went on for years and if you search other forums' threads was, possibly handled even worse than the original game's release. Development went on for years with little news or end in sight. Meanwhile, other fans did finally make a restoration mod called TSL: Restored Content Mod (available here [http://knightsoftheoldrepublic.filefront.com/file/TSL_Restored_Content_Mod;111657]. If you're playing it now, definitely install that mod at least. It's well worth it and you have no idea how lucky you are that you can play it for the first time with this mod. I'm very jealous that you have that chance but I'm sure I'll enjoy my next replay in the future almost as much. If you're so inclined you'll enjoy a replay as opposite gender, light/dark side, class as well. And check out some other fun mods on that site linked above, there are some extremely cool ones on there.