Is it fair to ask my teenager to split cost of expensive shoes?

[BaconLegs]

He has a part time job. He is set on a specific pair from the mall, and it's just not in my budget.

I'd like to ask him to split the cost 50/50 as these shoes cost more than double what his siblings shoes cost.

I think it’s completely fine to say to an older child (which I assume he is as a teen with a part time job) “here is my budget, you can choose whatever shoes you like but extra money comes from you”.