The one thing this suuuuper Dutch person traveling (= me) does in (almost) all of the cities I…read morevisit: I hop on a bike. It's best way to explore a city and, in general, the fastest!
When going through Rome, I biked passed this store and thought "my bike needs a little tweaking"; brakes aren't working that well, bike chain needs some oil, one of the handles slipped off (yeah, I'm a fierce biker...). Walked in, asked if they could do some minor repairs and they told me to wait ten minutes.
The bike was fixed on the spot, even the tires got some extra air. All perfect, perfect. And then...? NO need to pay? What, why, eh, whuuuut? "How come", I asked, perfectly wiling to pay something. "Nope, that's our service". Well eh, thank you! What a great service is that?!
They sell all sorts of bike materials here and, as it looked, fair prices. They sell new & secondhand bikes for super reasonable prices (e.g. €40 for a bike); some classy 'hipster' bikes, rockin' beach bikes, racing bikes, and everything in between. So, there you have it - good service, good repairs, reasonable prices. Happy happy biking y'all!