What ships do you guys use for the courier bot, i am currently doing lvl 1 and 2 missions to get my standings up and i am doing a speedy 600m3 cargo hold ship.

Add 3x small cargohold optimization rigs to your frigate. When you continue with 3rd lvl, switch to wreathe with 5xT2 Expanded Cargohold II, 2x Medium Cargohold Optimization II and 1x Medium Cargohold Optimization I rigs. There are different opinions what to use on 4 lvls. Bestower/Iteron V or Wreathe. I would choose Bestower as it needs only Amarr Industrial 4 to have 40000 m^3 cargohold (max cargo of 4 lvls). Wreathe, by report of one user who made measurements, shows approximately the same profit.