GOG cuts up to 80% off a selection of game downloads and DLC for Windows, Mac, and Linux as part of its Best of Summer Sale, with prices starting from $1.49. Deal ends August 1. A couple of best bets:
Rebel Galaxy for PC and Mac for $9.99 (low by $10)
Soma for PC, Mac, or Linux for $17.99 (pictured, low by $12)
There are many ways for seniors to get cheap -- and even free -- entertainment and services.