[greedy_buffer]

If they were personalised it would be hard for sites like camelcamelcamel.com to exist, right? I would speculate that they don't personalise. Offering price discrimination as a service to third party sellers sounds like a minefield too.

[gnopgnip]

The price you see in the buy box is not always the lowest price. Anyone can click through and view all the sellers for an item. Sites like that track all the items for sale.

[fishbone]

Now that I think about it, price manipulation is probably illegal in most countries.