Carpet beetles drive me mad

Just over a month ago I discovered the lovely little creatures in my room and only my room. Cleaned the whole room it helped that I was doing a big sort in my room did every corner saw about 20-30 larvae nothing else took a few days to clean everything. Just for me to go to bed tonight and see 1 small nearly invisible larvae killed it and move one thing see like 4 more. It is currently 1am as I write this I can’t do anything.

How do they keep appearing in my room the windows never open I don’t have any holes to the outside just thinking about them makes me itch. I can’t do much when it comes to buying products cause I don’t have the cash any cheap alternatives until I get the cash to buy something hopefully more permanent than just vacuuming and washing things.