I'll be honest, this is a bit of an odd thread now, and I'm not really sure if you want advice/help or not?
It doesn't take a huge amount of "Googling" to find something that will fit the bill.
This took me all of 10 seconds to find a sub £30 pair of appropriate shoes in a UK5 - https://www.directbadminton.co.uk/adidas-ligra-7-junior-court-shoes-core-blackwhitecore-black-13836?ds1=&ds2=14450316171&ds3=130137966121&ds4=&ds5=c&ds6=&ds7=&ds8=&gclid=CjwKCAjw6fyXBhBgEiwAhhiZslSuMfHk8xbwy5RbxGj8UZv3ymqR2gpt6ZpRSstdJNQ_v4AwREsD7BoCBwgQAvD_BwE
As for the barefoot thing.... Would I do it? No. Have I seen others do it? No.
I don't think anyone would necessarily *say* anything if you played a UK League match, but it probably wouldn't be celebrated either.
Generally, players starting out don't tend to sweat too much - The movements/shots they know are less "explosive" and you aren't moving as much as someone who is experienced.
If you did sweat, you'd find that your feet would likely get slippy, but you'd also leave sweat marks on the floor - At that point, I'd expect someone to say something to you.
Ultimately, whilst Table Tennis can be an expensive sport at the higher end, you can get the whole kit for less than £100 (shoes, bat, clothes, balls).
That £100 would probably last you 2-3 years depending on how much you played.
My feeling is that if you want to take it semi seriously (as in, you enjoy it and want to enjoy it as much as you can), then the £100 would be the minimum expected outlay (you may even be able to do it for £70-80 depending on the bat, and what clothes you need to buy).
Thanks, I did post that I have now got a few ideas of what I need if I continue to play.