Good luck finding an English bulldog for $300.
They generally run from $1500-$2000. They have breeding problems that cause them to usually have to undergo expensive procedures.
I second the petfinder. We had an English bully at our local kill shetler a copule weeks ago but he was adopted (of course) on the first day he was available. He was only $90 which included neuter, shots, exc.
EBs are hard to find in rescue & shelters. They dont last very long, because everyone wants one, and everyone wants one for cheaper than breeders are selling them for. I know a girl who actually paid $5000 for a pet quality EB..
You might just want save your $ and research reputable breeders. I know of one if you want to PM me, not sure where you live though...But she should be able to tell you of one in your area.