eBay Sellers Hiking Shipping Costs

Newer eBay buyer. Don’t understand how whatnot and CollX lock in shipping by how the seller actually intends to ship based on type of shipping and the weight.

Noticing on eBay that sellers like to lower prices or accept offers after updating the shipping price.

Just got a 49.00 one raw card and didn’t realize the seller made the shipping 7.25 for card.

Would you negatively rate sellers that do this?