In all fairness friend.....you will not find a good one for that. Even used will be a trick.

Go to some gun shows. Stevens made some ok guns years ago and they're for sale at times.

Try Walmart. I saw one that is the former American Arms gun. They are not too bad but I don't remember the price.

The least cost good quality twin tube IMO is the SKB 505 and it's about a grand.