I want to find a cheap old topper to use 2 or 3 times a year. Does anyone know if I can fit an old topper on my 08 f 150 as long as its the same cab and box set up.

Older toppers will be different dimensions than your box.
One way to make it work might be to use some plywood strips along the bottom bolted to the topper and then clamped to your box rails to adjust the size to fit. Look on the popular "list" under auto parts will be tons of them for sale.

chuckwagon, sometimes the auto dealers that take trucks on trade-ins will have a rack of toppers that they've removed from said trade-ins. I know of 3 dealerships within 30 miles of me that have large racks of used toppers. Do a little looking around on the backs of some lots (you might even find one that's close to the right color!!) Phred52

Ahh good tip i will be sure to look into this thank you much for the help

if you are only going to use it 2-3 times a year and dont care too much about looks, then any $100 HSO-Classifieds topper that is close could be made to work.