It really takes no time at all to make a sauce!
chop some onion, peppers, garlic, carrot, whatever you like - soften in fry light (5 mins) add a tin of toms or jar/packet of passata, a tsp of sweetener and simmer for 10 mins. Leave chunky or blitz. My daughter has this blitzed and we have it chunky.
Syn free!! If you make a huge batch with double/triple quantities you can freeze it.
As an example though, dolmio light bolognaise sauce is 12 1/2 syns for a 750g jar.