This mic boom by Rode is nice. It's around $100 and is sturdy enough to hold "heavy" broadcast mics, such as the RE20. If you want a boom that will last, I recommend it or something by OC White.
But if you're using a "handheld" mic, such as an SM58 or ATR2100 (the mic I used to record this episode), there's a $15 option that may work well for you.
Listed as "NEEWER Adjustable Microphone Suspension Boom Scissor Arm Stand, Max Load 1 KG Compact Mic Stand Made of Durable Steel for Radio Broadcasting Studio, Voice-Over Sound Studio, Stages, and TV Stations" on Amazon, this isn't a bad boom. It's cheap, it's small, and it's not something that will last long with hard use, but if you're gentle with your stuff and don't need it for daily use, it's a good option to consider.
As podcasters, I think it's important that we embrace podcasting and how it's different from radio. And one of the ways that it's different is we can do something great for not a lot of money. For under $100, you can get an ATR2100 with the Neewer boom and, assuming you have a computer to record with, be good to go.
I'm showcasing how different people make their podcasts with photos of podcasts studios on the Big Podcast Instagram account. Whether you're using inexpensive gear like an ATR2100 with the Neewer boom or something pricey, I hope you'll send me a photo of your setup, so I can showcase it for others to see and be inspired by.
Don't Let Your Podcast Be Ignored - Download my free "Audience Attraction Cheat Sheet" to get 25 podcast episode (and segment) templates.