I buy as much of my stuff online at Newegg’s Electronic Store
I use a laptop, so a laptop stand recovers desktop space to store my notepads and post-its under. Shown here is the ALLSOP brand...
I also have only 3 USB ports on my laptop, but about 8 USB items to plug in. So a USB Hub is vital to keep me running efficiently. This is the Kikkerland Hub Man. LOVE IT and will own one soon.
I use a variety of color coded USB Flash drives. These are very inexpensive and get better all the time. The one featured below is a SanDisk brand (I only buy SanDisk - they have an "onboard" back up system on their flash drives.) And this is a screamin' good price on an 8 gig...
A second monitor keeps my email on one screen and my active project on the other. A very efficient setup, but not necessarily a cheap addition. In my humble opinion, Samsung is by far the best (featured link below) but also the most expensive. HP comes in 2nd but I can't stand their shiny screens. The glare is torture on my eyes. So I go with a matte finish LCD, I currently use an AOC monitor. Stay away from Acer brand, their display is blotchy and you can't tell a number 3 from an 8.