We have the litte wet/dry shopvac sold at Lowes for around $40 and it is perfect. Although 110 volts it works fine off the inverter
but is mostly used on dock
power. One nice feature to look for is dual ports
(a port for the hose to go in that exhausts rather than sucks). We use ours all the time to inflate the dink and it brings it to about 95% inflated. I never thought a vaccum cleaner was an essential part of our boat gear
until I bought it.