Most mullerlights are free. Vanilla, toffee, banana, strawberry, cherry, cranberry, mango, and the ones with chocolate sprinkles. The ones that have a cherry underlayer and the dessert (cheesecake etc) are not free, but they are low in Syns.
The Danone Activia 0% ones are free too. And the Weight Watcher ones too. But any with the fruit layer are sunned.
The SW website has a 'Syns Online' section under 'My Weight Loss Tools' that will give you the Syns for virtually everything you might need. If there are any particular snacks, etc you want to know the Syns of, just type the name of it in the search box and it should show you the Syns
Ask if you get stuck