We buy our landscaping mulch in bulk (scoop loads) at our local greenhouse. I don't know where you can buy it, not sure where you live. You should google mulch by the scoop and your area and see what comes up. 1 place here is $50 a full scoop and the other place was only $35 a scoop, so check around.
you can get that in Garden stores or in any local Garden center, you can ask then for bulk purchase.
Other people asked questions on similar topics, check out the answers they received:
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them