It sounds like it could be the way your shipping rates ( Settings > Shipping and delivery) are set or they may be capped at less than $200, which would be why the items are not displaying for customers when priced over this.
Or it may be the way your products are set up, and how they are shipped. Are your products set to ship via weight or price, or just using the courier's service? You mentioned you are using USPS First Class package for instance.
Has this only recently started to happen, or has it been an issue for a while? If only recently, did anything change in your store around this time?
Can you share your store URL, and I'll try to test the pricing myself and see if I can identify the issue.
Let me know how you get on, or if you have any further questions!
All the best,
Hank | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog