I'm considering purchasing a car but it has rather subtle scratches on two spots:
I don't have extra money to fix the scratches now but in the future, can these be fixed, how and more importantly at what cost roughly?
If just the clear coat is damaged, you can do a wet sanding technique. You can Google "how to buff automotive clear coat" and there are tons of different things you'll find. Clear Coat Buffing
If the damage is to the color coat or deeper, you'll probably want to get it done professionally because the color can be hard to match and getting a nice finish does require some technique.
All of that said, I don't have the most experience on finishing automotive surface on this stack. Others may have better input. Doing it yourself will be the cheapest option, but will require the most time and effort and may result in a bad result depending how well you end up doing it. Getting it done is the easiest, but neither I nor any other user can really comment on the cost thereof.