A few people have been scammed on the site, Only use paypal to pay for items for sale by other members. If they will not use paypal, its likely a scam NEVER SEND E-TRANSFERS OF ANY KIND.
I really cannot make myself spend the dosh to buy a Tom Tom or Garmin bike type GPS -when a simple car one can be bought for £30 on ebay. The waterproof box works but it not neat and condensation / bright light ,makes it less than perfect.
So toying with making a mount ON or cutting in the GPS...