I got a big cardboard box, covered it in like a fleecy felt material from ebay cost £2 for like 4 meters!
Cut a hole in the front, and the top and they love it!
Dalia hides things in there! Like £20 notes, sock, underware! Just whatever she finds lying about the house!

I also had a spare ball of wool, boy did that go down well! It was big chunky wool and they loved it! I pleated bits of it and they carry it around by those bits and have a lil tug of war!

Also we got a bag of cat nip and made felt fishes!

I prefer to make my own toys! If you make them yourself and they dont last long you know why but if you buy them from a shop and pay loads for them its anoying when they break and with 4 cats in the house we go through toys like my cats go through food! FAST!