You get what you pay for when it comes to boat covers. Custom is by far the best way to go, but alos by far the most spendy.
The best of the cabela’s trailerable covers are actually pretty good and hold up well. I think for most boats they are around $200. The way they strap down is a little more labor intense than most custom covers.. but they also cost less than 1/2 of a custom cover, and travel very well.
If you do go with an over the counter cover.. dont get the inexpensive ones.. they are only good for sitting in your driveway in a less than harsh environment. They will only last a season or 2 just doing that.
You get what you pay for. Dont skimp if you want it to last. Some over the counter covers have good warranties and that makes a difference in items like this.