Bass on a budget! Looking for a 12 inch sub to have installed on a 2001 Honda CRV

I had my stereo rewired with rcas and had new pioneer 3 ways installed. Looking for a 12 inch sub and amp maybe even dual 12s. Space is no obstacle. I have plenty of it. Only issue is budget. My budget is 200-300 dollars. I already have a powered 10 inch Rockville sub in it. Looking for an easy installation to save money. The shop told me all they would have to do for a powered sub is just swap the wires. However more interested in a box and amp that's complete. I don't have any friends to install it for me. Almost none of them even drive lol.