"Wattage" on a cheap amp is like a blind man looking for a hooker. You never know what you're gonna get, but you've got something.

Save your money and buy decent equipment vs rushing out and getting cheap equipment now. It will be worth it. You will end up hating the sound and end up buying something better anyway.

Quality of the equipment and install is far more important than if you have "enough watts" for X sub IMO.