I don't mean to be spammy but I stumbled across this thread today and thought I would give a little input. First yes, I provide merchant accounts, but I will try to be unbiased here.
A couple of possible solutions:
1. Wireless credit card terminals. This allows you to swipe a card on site, gives you greater chargeback protection, and a lower rate because the transaction is swiped. Downside is upfront money, and or lease costs can be prohibitive. In addition if you have several trucks running around to you might need multiple terminals.
2. Software. Considerably less expensive option. Their are quite a few options out there. The benifit is for someone who has a lot of lawns they are billing monthly as several types of saoftware allow you to set up automated billing. For instance if you are billing 200 lawns on the first of the month, you only need to enter the credit card information one time. For each successive month the transaction is automated. Benefit is obviously convenience. The down side is you are now looking at a non swiped transaction so it will cost a bit more.
Hope that is of some help. If anyone ever wants some additional information on merchant accounts, feel free to email me.