If you want to be right alongside the Dordogne river then Soleil Plage and Port de Limeuil both get good write-ups. We've been to Soleil Plage, and liked it very much, but in peak season it is very popular and expensive. Out of season it takes Camping Cheques - a very good saving over the normal site price. Port de Limeuil takes the ACSI card up to the 7 July, and after 24 August, and at 13 euros is very good value.