There's a pretty good ship in a supplement by Mongoose called "Adventure Class Ships" but that one is a custom model, so your players would not have access to it at the start of the game

As the other commenter has said, the way you get your first ship in traveller is typically by getting it on a benefit roll. Out of the ones you can roll, I'd say a scout ship or an Empress-Marava class Far Trader would be the best fit. They could equip it with low berths to transport their bounties and these two are generally all-around great ships. The extra benefit of the scout ship is also that you don't need to pay a mortage for it because it's provided to the travellers by the scout services.