Oh yeah, totally forgot about the dump insert. Dude you're just trying to take it all on too fast. You'll drop $7K into a truck with a dump insert, that would be a TERRIBLE investment at this point. Most of the landscaping you'd actually be capable of doing at your age wouldn't require a dump insert and if you need materials just have them delivered on the customer's dime. For landscaping, I suggest all you try to do is plant plants, install mulch, plant some trees, maybe do a little stone work, NOTHING MORE right now. If you try to take on too much it's possible you're going to get slapped in the face by a mistake that will cost you money or you're going to realize you're in too deep. Like I said man, not trying to hack you down, you just gotta realize that you're buying all the equipment before the business, I know exactly how that goes, I used to do the same thing. Big dreamin' is fine and good, but just do yourself a favor and kick some @$$ mowing lawns and light landscaping, you gotta get off this landscaping thing it'll ruin you man, there's a lot more to it than you think.
Go hard, go fast, or go home