Is it a bad idea to buy an internal drive for my MP from a site like Amazon and have it shipped to my house. By bad idea, I mean potential for damage from shipping, not obvious damage, damage that could cause problems later?
There are two general classes of drives you can buy. Those in "retail" boxes and OEM "bare" drives wrapped in a antistatic sleeve.
If it is a retail box drive then it is probably OK no matter who you get it shipped from. The shipper should put in some redundant padding so the internal box doesn't widely bang around, but the retail boxes are usually pretty well designed to protect the drive.
If it is a drive in a antistatic sleeve/bag then how the vendor packages the drive is an issue. Amazon and OWC typically use quality boxes and stuff enough packing padding ( air bags , corn packing peanuts , whatever bio-friendly material on their short list) and ship them off. Some other folks don't do as good of a job.
OEM drives are usually shipped to stores ( at least stores that sell alot of them) in a bigger box with better padding for the drives. It is only when they are "repacked" into smaller lots for shipping that gets removed. Your local BubbaGump small volume PC parts store might be getting them newegg and it is no different.