Well thats not the best photos to identify it from. And I'm surprised no-one has chimed in yet.
That seems to be a Douglas TS model (?), a 2 speed belt drive with the tram handle gear change on the tank.
Someone who knows them better could probably nominate a year for it - but it seems to have no brake on the front wheel ?
Some models have the year stamped on the timing cover (?).
Where to sell depends on where you are.
And how well it cleans up, and the overall condition and completeness.
And if you have any history. And how good the photos are !
Hopethishelps.