Usually, an Apollo with steel rims is something I would avoid. But free? Great! And its a mixte which makes all the difference IMHO.

It has several of the typical bottom end features many pointed out above to avoid: steel rims, turkey levers, nutted axles, claw derailleur hanger (guess on my part), steel seat post, stem shifters, stamped steel side stand, steel handlebars, very likely high ten steel frame. If it was not a mixte, in my area I would take it directly to my favorite thrift store and donate it, as it would not be worth the time or $$ to rehab. But as a mixte, it will command a nice premium.