Get a fabric one. In a pinch they sell the same sized grow bags. I’ve also seen especially made compost bags. Still need to agitate and mix it for fastest results. You can go grizzly like I do and roll it around and generally mess it up a bit then put it back together. Smart Pots 12120 Compost Sak Fabric Composting Container https://www.amazon.com/dp/B008X0M30Y/ref=cm_sw_r_cp_api_glt_fabc_GYQ9XNQ2BQB1WQ9SR1HG
If you have access to a truck, Orange County Farm Supply in Anaheim offers a ton (literally) of compost for $20, plus another $20 bag deposit (you get the deposit back when you return the giant bag). It’s the best price I’ve found in town.
I’ve started my own compost pile (using this: Smart Pots 12120 Compost Sak Fabric Composting Container https://www.amazon.com/dp/B008X0M30Y/ref=cm_sw_r_cp_api_i_8HyoFbC45QFF6), but it takes a while.