Something that some people regard as a bit of fun but others really make an additional extra cash.
This is comparatively easy so no long tutorials here !
Basically, just as Casino sites and Bingo sites offer free offers so do Bingo sites - by the thousand !!
They all vary considerably but have the same principle - deposit some money and they will offer you a hefty bonus. Treat it as a bit of fun and make some money at the same time.
You will see that Cash-Matters list the current best offers. There is no intention here to patronise or bore you with the detail. The forums discuss the latest offers which can come and go in a day. Well worth a good look if you have the time.