Withdrawing DFI from Cake costs a flat fee of 0.2 DFI, which is about $0.60 at today's prices. Selling to USDT and then buying DOT costs very little, and withdrawing DOT to Kraken costs a flat fee of 0.1 DOT, which is about $2 at today's price.

So, it's about $3-4 for the whole end-to-end transaction.