My formula is pretty simple. I use $.50 per linear foot for edging around an existing edged out bed and $.75 if it needs bed prep and edging. I charge $75 per yard of hardwood mulch installed, extra if dyed mulch. Any bush trimming I add $7.50 for small items and $15 for large ones including haul off. I will use these numbers for getting my total price but I don't break it down for the customer, its not really something they need to be picking apart. I have found the best tool for bed prep is a mini tiller. Mine is a Stihl FS56 with the trimmer head removed and tiller head attached, a very profitable tool.
Knowledge is knowing a tomato is a fruit, wisdom is not using it in a fruit salad.