Hey, I'm about to start my first background project and i was able to collect different pieces of polystyrene but i couldnt find any plain sheets. I looked for them online and they cost way more than i expected. I asked people and shops but all i could get were box pieces and packaging pieces. Are there any specific shops that give those sheets as trash? Is there any way of getting them without paying 30$ a piece? Btw, what grade and thickness is recommended for a background? Thanks in advanced!