Don't know if this is any use for folk, however, was browsing locally the other day & found in the clearance.
"Bamboo" 0.6 litre bento boxes (thermal walls, leak proof IF you take care loading / wiping sealed edges) for £2.45 ..ok they were the kids version (with japanese hipster type cartoon graphics on them, .which I liked)
(Note: 5 mins microwaveable without lid on)
& Thermos brand stainless steel vacuum for around £4.50, 290ml food flask (looks like an old version without a knurled, therefore slippy smooth lid) ..if you are chowing "leftovers" or bagging up lunches & doggybags for others.
Longshot I know with folk scratching their heads, as to use within their set ups, but I find I can never have enough thermally lined containers & wot-nots which get put to use (even outside of a bbq "baste" lifestyle)
Might be worth a look if you are passing.