When we were first married (50+ years ago!) we had very little money and ate coley frequently. At that time many people saw it as for cats only and so it was very, very cheap compared with other white fish. It does have a slightly off-putting greyish tinge when raw, but becomes white when cooked. Sadly over the years more people have realised it is very good, and although it is still cheaper than cod, haddock and hake the price difference is much less.
We also eat pollock, perfectly acceptable. We had a brief holiday on the North Norfolk coast recently and treated ourselves to a 'small' fish and chips at a restaurant in Cromer. The waitress whispered that it was pollock, presumably some customers expected a smaller portion of cod. It was very good!
Our freezer is mostly used for storing yellow-sticker bargains, usually fish, meat and berries. Morrisons often has fresh blueberries and raspberries at 10%, (ie 90% off), and we have also had steak, lamb chops and expensive fish for 20% or 10% of the full price.
In summer and autumn OH forages for wild cherries (sour but good cooked), mirabelle type plums and blackberries, much of which is frozen.