There are a ton of posts on covers for your trailer. But in order to access them you must be a lifetime member. It's only 35.00 and I guarantee it will be well worth it. This is a great forum. Lifetime members get some bennies, including the search function (I'm sure others will chime in about this too).
Regarding covers for your RV, you can spend anywhere from $200 - $1,000. We have a Calmark for our pickup (we are not physically able to climb on our trailer). It's the best quality (we paid about 800.00 a few years ago) but the price has increased quite a bit since Covid. Some people no longer think it's worth the money. Others spend far less and think it's worth replacing every couple of years. We get a lot of wind here and we see covers torn to shreds on a regular basis in our storage unit yard. Whatever you choose, remember you get what you pay for - but if you get one and you get a lot of wind be sure to secure the cover tightly.
Bonnie