Honestly, most jars of sauce will be quite high in syns. I think aldi do a pasta sauce that about 5 or 6 syns and the WW ones will be lower but you can basically just use 1 syn per 20 calories to work out any shop-bought sauce. Far better just to do your own and really easy as well as being syn free. There are lots of recipes in the recipe sub-forum
If you microwave a hexa Kerry low low spread (60g) it gives a nice cheesy sauce for pasta as well (also REALLY nice for dipping veg sticks in when warmed up... Yum)