You are setting up to record clean audio that sounds like it belongs in a studio, not a tin can. A solid professional podcasting microphone and interface kit should last you years of heavy weekly recording, so you only want to buy this setup once.
Keep an eye out for holiday bundles that throw in the boom arm, shock mount, and XLR cables for the same price as the bare hardware. If you time this right around major sales, last year's interface model is often deeply discounted while offering the exact same audio conversion quality as the newest drop.
Remember that the 0% intro APR for 15 months on purchases and balance transfers is a deadline, not free money. If you still have a balance left when those 15 months are up, the standard interest rate will kick in on what you owe.