I work in a shop that participates in TGTG - we often offer 2 bags at £3:39 each with a value of at least £11:90 (bag value and price are set by head office not us but we choose what goes in the bags from our yellow stickered stock; focusing on items expiring on the day we get them not the next day) We do not include hot food in the bags as that stuff has a specific time limit from cooking to being discarded which is outside of our collection window. We also generally don’t include more than 1 of any single type of item (so bread or a pastry for example) but may include 2 different fruits or vegetables.
Ive also bought TGTG bags and find some places are more generous than others - our local Greggs do both a morning and an evening bag and they sell out quickly, weekend morning bags are usually more readily available (who wants to be up at 7am on a Sunday for a bag of out of date food?) and, last weekend, we got £18+ food for just £2:99; it meant we had a picnic lunch on Sunday from it and a sweet dessert treat in the afternoon too.
Worst one I got was from a deli cafe type place with a naive food shop attached; the bag cost £5 and was meant to have £16 worth of food in it, there was a pack of 2 stale finger donuts and a tin of 8 shortbread cookies flavoured with lavender which was part of a Queens Diamond Jubilee themed collection - the donuts were apparently worth £5 and the cookies £12 at full price so they met the price requirements but they really weren’t worth the £5 I paid.
I think if you live in a town/city with lots of options, you can do really well out of TGTG but, if like where I live, it’s a convenience shop, a petrol station shop, the pasty/hot counter of a supermarket and Greggs with a couple of artisan hamper companies occasionally sticking out a bag of over stocked items, pickings can end up being slim