Couple of tips from a fellow rat owner....
Teatowels make great hammocks. Pop a large paperclip through each corner and hang (or fold in half, then hang, for a pocket hammock suitable for smaller rats). I dont waste £5-10 per hammock just to have to throw them away each change - 29p teatowels from Asda, and no worries about the design going out of stock
Cheapy oven gloves make good pouches for tiny rats, bigger rats you can make them out of thicker cushion covers (great for getting scared rats used to handling, pop them in an open cushion cover on your lap).
Rope dog toys can be altered to make great rat ropes. Poundland do some rope dog toys with a tennis ball on the end. Cut off the tennis ball, you have a loop of rope. Cable ties around and hung with paper clips - hey presto, rope bridge!
Hamster/rat balls - unsuitable for their original purpose - make great igloos, hung with some garden wire in the corner of a cage, and stuffed with kitchen roll or shredded paper.
Bigger cereal boxes also make great igloos for babies - plus they get to chew them up, more fun to be had. Toilet/kitchen roll inners also make great tunnels for kittens, for bigger rats - the heavy duty rolls carpets are stored on - try your local carpet fitter or shop for freebies, or ask on Freecycle.
Wooden parrot toys make great rat toys too - look on ebay or shop around to find cheaper ones.
Hope that helps a bit!
