you should be able to find a kids camping set at the sams warehouse for 20-30 bucks which have cartoons and are colourful and have a sleeping bag, mini tent and air mattress. Kids sleeping bags are really thin, so you'll need extra blankies but they'll love having their own stuff. You can pick up cheapo kids fishing rods and yabby nets there too, essential gear for kids camping lol!

I agree with the portable toilet though, if you have that much extra cash, rays outdoors usually have them somewhere about 100 bucks, definetly worthwhile!