Apologies for not making it clear. I am on a Mac and am looking to purchase a physical copy of both eventually but one for now.
In all likelihood... You could get Fallout for PC (Windows or DOS) running on a modern Mac (via emulator), for far less than 80 dollars. Fallout runs on a Pentium 90MHz CPU and needs sixteen MB ram. I would buy both GOG versions just to have them for later.
*You could also buy ANY
[IE. the cheapest] PC from a thrift shop to run the game. Fallout needs no 3d card, and will run on any integrated video & sound.
**I've found PC's that would run Oblivion for less than $30...
(though I'm just lucky that way B)).