There's lots of info on here re good bunny toys. Here's a few budget buys/makes mine like:
Loo rolls filled with hay
Cardboard boxes with doors cut in
Little children's seats that buns can jump on
Plastic Baby building blocks-pile a couple up and buns knock them down
A few sheets of newspaper/paper packaging-they love to rip these up
Plastic skittles-Milly loves bunny bowling
Baby teething rings-hard plastic ones
Paper bags filled with hay and/or a bit of food. Scrunch the end up and buns will rip it open.
A cat/bunny tunnel
Many of these are available cheaply and charity shops are a great place to find baby/toddler toys. Give them a wash and always keep an eye on toys to endure they're not getting too chewed.
Lots of bunny toys are rubbish anyway, but willow balls (from pet shop only not decorative ones) go down well, throwy toys and the big balls with a bell in tend to be popular.