One class of ship to use is the cargo frigate. A class of ship more often used for exploration due to its probing bonuses, the cargo frigate may just be useful to those who need to move limited amounts of cargo around. The frigate with the most cargo capacity is the Amarr Magnate, followed by the Matari Probe and Gallente Imicus. With 3 low slots, when rigged with Small Cargohold Optimization I, 3 Extended Cargohold II and the racial frigate skill trained to V, the Magnate can hold 1009 m3 (see note below) of cargo while the Probe and Imicus, with only 2 low slots, can hold 989 m3 of cargo. This is important because with that cargo capacity, all three ships can hold one Large Standard Container and one Medium Standard Container, increasing the cargo capacity for small items by 195 m3.
This leaves the Heron, the Caldari cargo frigate with only one low slot, such a poor fourth choice for moving cargo around I didn't bother
Please note that flying a cargo frigate will make you safe from those killing ships in high-sec during Hulkageddon IV. If pirate gangs start using smart bombs around a gate, your ship most likely will die. But at least you will not be a target.
Note to self - Don't correct yourself. The Magnate doesn't get a cargo bonus.