With a budget of $600, skip the bespoke suits, check out English accessories and OTR stuff:
Selfridges, Harrods, maybe Liberty's -- check out Drakes, Peckham Rye, and the shoe departments ...
Gieves and Hawkes post Christmas sale (Savile Row), Benson & Clegg has ties too (Piccadilly Arcade) .
Walk along Jermyn Street and drop by Turnbull Asser to see what's left from the sale.
If you're keen on good English shoes that won't break the bank, check out Cheaney, Loake, and Barker (in that order).
Bridle bags etc -- See Pickett (Burlington Arcade off Bond Street) and Sage Brown (Prince's Arcade).
This way, you cover all the notable establishments from high street fashion to classic Savile Row.
Go to all of these places to check out what you really want to buy, before dropping money on anything, so you can stretch your pound/dollar. I'm saying this because whilst $600 is a tidy sum for a college student, it isn't all that much for one to spend on expensive products.
Best thing to do is to draw up a list of what you need, for eg, one bag, one pair of shoes, couple of ties etc, and cover all the basics, and then if you have money left, buy some additional stuff. Better than blowing all $600 on a pair of shoes for example.
And ask to claim the VAT on your purchases.
Edited by bboysdontcryy - 12/25/12 at 2:23am