you going to get answers from a lot different prices
average price will be around 200 -250
what ever you get .... get ones with bluetooth
I would go with average prices and look how LONG the seller has been selling them
less than a year ... NAHHHHH skip that one
I bought Elfhub on Amazon 200 each last April
4000 miles and they still work
but if you intend to use a Inverter look at brands with a reputation of powering Inverters
you might pay about $50-100 more
Solar
to work good you need at starting solar setup of around 400-600w
I have 2 panels x 370w each ... fits nicely
50 amp mppt
2x 100ah elfhubs
spent around $1000.00
I only use solar to charge the battery... boondock on battery and solar only
only use 120v shorepower when I want air conditioner
Have save almost $450 this year on camping fees