Think most are nowadays, but it's worth getting one with a removable pot - easier for washing up [or soaking if you have to].
Brisket [cheap joint] cooks well in it. Usually put a layer of onions in the bottom, sear the joint, and add to warmed up crockpot [I usually put a kettle of boiling water in it & turn it on while I get the food ready]. Pour over about a pint of gravy or stock, leave to cook overnight. You can pearl barley, dried veg or soup mixes.
Try these :
http://www.slowcookerrecipes.org.uk/
http://slowandsimple.com/
http://www.slowcooker.org.uk/
http://www.cookuk.co....ker-recipes-index.htm
Don’t overdo the liquid though as it can get watery. Enjoy.