I am looking to buy a new mountain bike off ebay however, the vendor who is selling wishes to add duty plus vat which totals £228. with delivery and original cost of bike it will be 1350 dollars
how can US verndor do that? duty and VAT is charged by UK customs.
... and UK cutomers are no fools, they have departments that figure out ways to fleece you - items posted to UK must have a value declared and they will base the duty/vat on that so putting a low figure may not guarantee success - parcels labelled "gift" or "free sample" may be exempt fom duty as is seen often on ebay but you need to look into that.
I suspect you won't get away with it - one option could be to fly to US on a cheap ticket?