Not sure if this qualifies as "Things I've bought" maybe more like "best money spent".
Membership and donations to the Charles River Conservancy and Livable Streets Boston- 2 organizations that proactively advocated for improvements to the Charles River bike path and bike lanes on Commonwealth Avenue- my 2 routes into work. After 30 years of riding an inferior and crumbling bike path and battling for respect and space on Commonwealth Avenue these improvements have made my commute easier than any rain gear, cycling shoe, pannier, studded tire...
They have also made the city more bike friendly with more bike racks. MASS BIKE, was useless for about 25 years with regards bike infrastructure but they've finally changed their tune and I've appreciated their past efforts to allow access to public transit for cyclists. The bike racks on buses and particularly their efforts with commuter rail trains has made some of my longer commutes much better.