I was thinking it over and decided not to buy one. Reasoning being I don't really need it.
I am only part time, so most likely once I pick up a few clients, i won't be adding anymore unless I lose a client or expand. Secondly, for simple residential mowings I can just fill out a sheet by hand with the cost break down, and the total it would be and give that to them, once the service is payed for I can fill out a receipt slip and keep one for myself and give them one if they want.
As for printing invoices, I don't really need to do that either, unless the client really wants an invoice every week, I wouldn't have the need to print one.
For everything else, I think i'll just make up a simple log book to keep track of time, and stuff like that, and then enter it in my computer at a later time.