Let’s Encrypt certificates are free of charge. Renewals (which are required at least every 3 months) are also free of charge.
However, there’s nothing stopping your hosting provider from charging you a fee to use a Let’s Encrypt certificate with their hosting, and at least one well-known hosting provider is unfortunately known to do this. If you’re in this situation, and can’t switch to a different hosting provider, you might find that it works out cheaper overall to buy a cheap certificate from a commercial CA, rather than repeatedly paying your hosting provider to install your new free certificate every 3 months.
(I had trouble understanding your question so I hope this information is useful to you)