I'm not anywhere near Texas, so I don't know the "going rates" down your way. I've taken on mowing quite a bit of property this coming summer for an "asset managment group" that handles estate property and/or properties owned by elderly who are stuck in a nursing home. By doing it this way, I'm only dealing with one "customer". We've already done some business. I finish the job, call in my time, and a check appears in my mailbox in 2 to 3 days. Can't beat it with a stick
My insurance is written as a rider on my farm policy. 1 mil liability coverage cost is right at $350 a year that way. In todays sue-happy environment, I wonder if that's enough.
Any time I've ever done side work with my equipment, the biggest drain on my intended profits has usually been hauling/transportation cost. Your time must include something to cover that.
I've ran in to a few people that want "fixed price" numbers, but most will go with the hourly rates.
Don't try to get EVERY job you look at. Some will throw up a red flag on first sight. Stay away from those. ("Bad karma" with the customer, junked up property that will damage your equipment, and/or conditions you just don't like.) Let your competitor have them. People that tend to gripe and complain before you even start automatically get bumped off my short list. Make certain of what your lien rights are should you get someone who won't pay. (That happens more nowdays than ever before)
In time, you'll be able to build a client list that will keep you busy and will pay on time.
Here in rural Kentucky, should you ask $50 an acre for mowing weeds, you'll spend a LOT of time waiting for the phone to ring. $50 to $55 PER HOUR is acceptable. (assuming you can mow 2 or 3 acres per hour)