First thing you should do is look at what your competition is doing. Find out what the price range is in your market and how you're going to fit within that. Look at the equipment, common practices and the properties of your competition. A 50" ZTR is going to be a big waste of money if the residential properties in your area are served by 21" and 32" walk behinds.
Most people here always say figure out your costs and then you'll know your price. Your costs are critical, but don't forget your market research. Find out how much others are charging and what services they're providing and how they're charging for them.
If you've never actually done the work yourself (hardscaping, pruning, hedging), how are you going to compete with the experienced guys? Stick with what you know, or get real practical experience working for someone else before you can expect to provide quality service. You can only learn so much on the job when it's your company's reputation and (in the case of hardscaping) liability at stake.
As for estimates, avoid them whenever possible. Give your hourly rate for the service and, if asked, a ballpark guess on how long it will take. Don't back yourself into a corner with a bad estimate, you'll either end up losing money by taking too long or you'll lose money in the future because you rushed the job and hurt your reputation. Obviously most material based jobs (like mulch or turf) you'll be expected to provide an estimate, but for pruning, hedging or general yard cleanups... every job is different and you might not really know how long it will take until you actually start doing it. With all that said, this is also something that will be dependent on your market. If everyone else is giving fixed quotes for doing a hedge you might have to do the same.
Keep your costs down as much as possible until you know what your true real world costs are. Until you have real data (first year) to look at your just going to be guessing.
Finally don't start out in debt. You might be better off saving as much as possible for a year before you start up. If it's practical you might even be able to spend that year working for someone else in the field (although it sounds like you have a good foot in the door with the snow plowing).
Edit: Forgot one thing. Establish a relationship with a local shop who's going to service your equipment and sell you new stuff. If you buy something used, make sure it's an established brand in your market so that there are local dealers who regularly work with and have access to the same parts. Even though it will probably be more expensive than the private market, you might be better off long term by buying your (big ticket) used equipment from a local dealer.
Last edited by Reflection; 02-06-2013 at 10:15 PM.