I used a 120GB SSD in my primary desktop ( used mostly for gaming ) from 2010 to 2013. If you're somewhat careful about not trying to install a bunch of 50GB+ games you're fine. The largest game I own is Mankind Divided at 67GB. Add 30GB for Windows and programs and 20% of the drive for over provisioning and you're still under 150GB.
But I would consider a larger SSD. You can get a 1TB Mushkin Reactor for $220 and it's a MLC drive. There are 1TB TLC drives for around $200. 500GB for half that. Larger SSDs are faster and have greater endurance even though that's a nonissue.