I used up 0.99 GB out of my 1 GB allowance. So, I had to buy some more. My (former) operator, Orange, sells a 1GB package for an ultra-low price (not really) of 15 PLN. (You can get the same package for less money, even half of that price, with other carriers.)
How to turn that on? You can send a text message or call a robot. I’ll give them a call then.