A bimini should be pretty easy. Catalina Direct sells good ones, but there are lots of standard ones online for less money. For a C-22s, you'll be looking at a 3-bow bimini (the 4-bow models are longer than we need for a C-22 cockpit).
As
@rgranger said, measure the width between the mount point(s) you want to use. And then decide on:
--Aluminum or stainless tubing
--7/8" or 1" tube (1" might be hard to find in stainless)
--Plastic or stainless fittings (you can buy sets of SS fittings easily on Amazon or eBay, if you want to replace plastic ones in your chosen bimini kit)
--Type of material (Sunbrella is the biggest brand name, but is quite a bit more expensive than some competitors)
--Aft support rods, which will make it more stable than all strap supports (some biminis come with them, or you can add them later)
--You might add quick release fittings for the forward or aft end, depending on whether you want to store it folded forward or back.
--Bimini tracks (if desired) so you can slide the mount point forward or aft
You can figure on ~$125-400; you can definitely keep it on the lower end of that range if you need to.
A dodger on a C-22 will be much more of a custom job; they're pretty rare on our little boats. We don't have much in the way of side decks, so a dodger would make it hard to go forward. But if you do build one, please post pictures and experiences with it.