I bought a cheap chinesium city bike (but with fancy in-hub-generation LED lighting) for under $200, and it came with a "3 years of free checkups and repairs, 5 years accident insurance" plan. For those 3 years I brought my bike in every couple months and they'd clean it, oil it, align the brakes, and pump the tyres.

Additional repairs (wheel & tyre since I'm a fatass who also rides lazy and hard on curbs, some spokes cracked and the tube split) are another $100.

I pump tyres at home with a $15 hand pump, and relube the chain with oil cans from the dollar store.

So a total outlay of about $300 in 5 years of riding. I guess it'll survive another 2-3 years before it's cheaper to just buy a new one.