Previously I used to buy Cathedral Cheddar at Villa. Pretty good value, THB 209 for 250g. Now it's THB 320! Switched to Mainland from Makro but as has been mentioned above it's been out of stock for some while, replaced with a pretty bland (albeit cheap) HoReCa cheddar at THB 349 per kilo. I tried as we were out of cheese and I was done on the cheese hunt for that day. At a real push I suppose it's OK for grating onto whatever but it really is bland otherwise. Can't expect much else for the price I guess. Mainland has been out at all the places I shop (and can be bothered to go to) so I'm guessing there's a freighter due soon.
I also used to buy Brooke baked beans in preference to Heinz, not much cheaper but a bit. Tasted just as good but again, not seen any for a year or more now, mostly replaced with Watties that are not so nice.
Mostly I try to buy from Food Variety via Shopee, it's delivery prices are cheaper than Siamburi mostly.