Travelling to the USA on a one way ticket- will I have customs and immigrations problems?

We are going on a road trip for 3 months and meeting in Canda, then going to move on around america. I have only bought a one way flight, then will go to the airport on the way back and book another flight.

Am i likely to have difficulty getting through customs?

Thanks!

more than likely. they usually like to know your whereabouts. and also what money you might be traveling with. if case you might jump ship so to speak and want to become a resident with out visas. perhaps you can buy an open ended return ticket. one thats valid for 12 months. and simple book the return date once you know it.

The Visa Waiver Program requires that you have a "return trip ticket to any foreign destination". It is not clear if Canada qualifies as "any foreign destination" because going to Canada for a short trip after entering the USA on the VWP does NOT count as "leaving" the USA.

I recommend you avoid the problem by simply getting a round-trip ticket with the departure date a bit less than 90 days after your USA arrival date.