Few quick questions :)

1.) Do guinea pigs like hammocks? If they do, any hints on making them?

Some do, some don't. Mine aren't keen but some love them. It's worth a try as they're easy and cheap to make. There are some tutorials on the forum in this section, should be up the top as a sticky. The one I made was done from following a tutorial here - the one with a flap at the bottom so it doubled up as a hidey. They used it as a hidey, but not a hammock.

2.) I have 22 square feet of floor space (the level not included), and as most people give their guinea pigs floor time, I was wondering if I should? But I'm not sure if floor time would actually benifit my pigs, as my cage and bed take up way over 3/4 of my room. That also doesn't include my chest of drawers. So really, they would only have a little bit of space, as in the outskirts of the room to run around.
Should I let them out anyway? If so, how often?

Again, could be worth a go. The main purpose of floor time is so that guinea pigs have space to run round and burn off some energy at their leisure. But, with a cage that big and limited space round the room, it's not hugely necessary - give it a go a couple of times a week and see how they benefit from it. They might enjoy the freedom! Make sure your room is 'pig proof' first.

3.) Do guinea pigs like their cages to be changed around weekly? With different toys, and such?

I change a couple of accesories here and there when I wash certain ones, some people do it to stop the pigs getting bored. Maybe have a double of extra things so you can switch them out every couple of weeks, although if your pig has a friend and lots of hay, they might not mind too much!

4.) Have you guys got any homemade toy ideas I could use?

Check out the forum for tutorials And search them in the search bar. Or google I know a couple of ones some people do is to stuff a cardboard tube with hay/treats etc, or a sock. Although it's being said that you shouldn't give pigs any cardboard tubes with glue on so watch it for it

Thank you!!!
I literally just noticed the stickies about the toys and hammocks.
I'll give floor time a go, and once I get my new bed, in a couple of weeks, I'll be giving a bit of floor time

No worries I know floor time can be a bit of a pain sometimes but it's worth it. I've been sneaky lately, it's so much easier for me to block off the kitchen floor and let them toddle around in there so when my folks go away I've been doing that instead! Lino flooring makes cleaning up much easier lol

Just a word about hammocks- as @iamsnape said, some piggies love them and some don't. Mine turned out to be the latter, but they love to hide under it, so it really works either way

My guinea pig is in love with her hammock. She sleeps in it all the time!

I would say experiment with a hammock and see if your pig loves it. If not, she might hide under it, as @Crazy Cavies said.

Thanks for the tips guys I think my guys will love hammocks, because they love the loft in the hutch