Good news, the part is cheap. Bad news, its hard to replace. Your drum bearing is shot and needs to be replaced. I am not an appliance guy, but was able to DIY this repair. The biggest problem is that you have to completely disassemble the dryer, remove the belt, pull out the drum then unscrew the bearing and mounting. The replacement kit includes spindle, bearing and mounting hardware, and.... best of all...instructions and pictures.
You should be able to order the part from an authorized parts dealer.