All riverine traffic and activity takes place under the aegis of the Ingilli Family, and that includes building, selling and hiring boats. There isn't one boat yard in Pavis - various boat builders exist along the river bank, but they all produce boats for the Ingilli family, and will only sell or hire via a representative of that family. Hence prices are consistent no matter who you approach.
Wood is a rare and precious commodity in Pavis, especially wood that is good enough for boat (or house) building. The nearest source is The Garden in the Rubble, but the Aldryami get very aggressive if you try and cut their trees down. The only other source is the forests of Dagori Inkarth to the north, but that is troll territory, so logging there needs cooperation from the various troll clans. As a result, most of the boats on the River of Cradles are built of reeds, which are plentifully available. Reed boats normally require considerable repair and rework every year though, as the reeds rot and become waterlogged.
Price List (to buy)
Newtling reed boat: 4-6 metres long, normally crewed by 2 newtlings, and can carry another 8 newtlings - 25 Lunars
Three-person reed boat: wider than the newtling boat to provide more stability. Can carry up to three people - 35 Lunars
Ten person reed boat: suitable for either people or light cargo - 100 Lunars
Coracle: small and hard to manage, but easily transportable and made of animal skins over a light wooden branch frame - 5 Lunars
Riverboat: a shallow drafted wooden cargo ship suitable for riverine transport. Around 10 metres long, it can carry up to 5 tons of cargo and requires a crew of 8 - 250 Lunars