I'm being honest because I think that is what you want, and I don't want to waste your time.
The reality of making stuff by hand is that automation of simple knits like hats has reduced the value of the skill to virtually zero. As people have said, Primark hats go for next to nothing.
The only way to even sell handmade things is if they are incredibly unique with some kind of artistry AND that this particular quirk is to someone's taste. The likelihood of finding your customers with not only the same taste, but enough money to spend on ephemera is fairly low. Not non-existent though.
To make a success of it, you'd have to find a niche where your skills can be put to use making something that can't be machine made, and also aren't being made elsewhere in the world where people are making piecework at $1 per day.
These niches do exist, for example there are things like personalised cards that people sell on etsy/ebay.
Even in crafts, there are some people selling hats that are beautifully hand knitted in natural yarns, with exquisite colourwork or textures. Or designer made, or in cashmere. However, it would have to be incredibly special to attract interest.
Clothing in this country seems very oversupplied. Not only are there companies like Primark, but also countless charity shops selling second hand stuff, plus ebay sellers selling on stuff.
There are also still an army of pensioners who love knitting and devalue the craft by making things in horrible acrylic yarns, with no particular style.
Its a very tricky market.