Adding a non-verizon phone to verizon?

ok well in september my plan expires and I'm going to renew my verizon plan but I want a new phone cause I have a crap LG vx5200 it sucks! anyways I wanna get a new phone but there arent many phones that verizon sells that I'm interested in and I wanted a samsung f700 or something like it and was wondering whether I can buy a phone that verizon doesnt sell and have it put into their network without like excruciating charges or anything like that... the only phone verizon sells that even slightly interests me is the samsung sch u740 but again I want something a little more high tech that will last better with technological increases and idk whether verizon allows that or not so anyone know what I can do?