Things to do for free?

Me and my fiance get into a fight about this very question almost every day. He claims that because we have no money to spend on extra things right now, then that means that we have to resort to the same things we do everyday. Watch t.v., play with our 7 month old, and go on the computer. Hes starting a new job in 3 weeks so for now I am just trying to come up with a few things that will keep us all entertained. I can tell that my 7 month old is getting very bored of doing the same things all the time as well. Keep in mind I read to him a lot, he cant crawl or walk. The only things my son can do is sit by himself and scoot around in a circle on his tummy. We take him for walks when we can but we live in florida so going outside isnt always an option. We play with him with his toys and helping him stand and crawl but all of this he (and me) is getting very restless and therefore whiny. I need some suggestions on stuff that will entertain us at home. We dont have the money for gas to always go to the park or the beach or a museum. Please help! So bored!