The Only 5 Pieces of Workout Gear You Need
Wooden Gymnastic Rings set -$32
Absolutely #1 on my list. With them and professor YouTube, these are infinitely modifiable to cater every muscle group from beginner to advanced. Here's a great example. Wood to maintain a painless grip long term. These take the place of dozens of sets of weights and it keeps you from cheating reps and practicing risky, harmful form. You can attach them to a door-frame pull-up bar or on some outdoor fitness equipment.
Cheap Yoga Mat - $5
Get down and dirty when you're on hard or dusty surfaces. Essential when an exercise requires your skeleton to be touching the floor. Plus, you'll appear much more well-rounded and respectable in your fitness acumen :). Five Below or TJ Maxx will carry them.
2 Exercise Bands with Handles (Medium and X-Heavy) -$5 each
Again, modifiable. Gripping higher or lower changes the resistance. Unfortunately it makes it difficult for bystanders to compare their strength to yours. Get them here or wherever else.
Foam Roller and Tennis Ball -$5
If you don't want to be active through your 60's and beyond then don't use these tools. Self-massage will help you explore numbed and ignored areas. You are head-to-toe one giant sheet of muscle and fascia. Not one square inch can be ignored. Moving (or not moving) unconsciously.