I think fun might be easier to come by than money.

http://whatson.brighton.co.uk/folk/ will eventually give you some pointers, although they haven't got May on the site yet.

The Lewes Arms Folk Club (at Lewes, not surprisingly) has this:
MAY 8 THE TRANSPORTS produced by Don Morgan
Songs from Peter Bellamy's folk opera performed by local singers & musicians. Floor singers welcome too.

On Monday 10 May there's a traditional tunes session at the Cricketers, Broadwater, Worthing.

Hope you find something going on - Brighton should be pretty lively at that time.

Marje