If you bike every weekday: (52 weeks/year * 5 days/week * 1€/day) + 12 = 272€.

Add in however much you think these bits of hassle are worth:

• various amounts of time spent looking for a bike, especially if you go somewhere they don't tend to cluster and someone else took the one you're using

• bikeshare bikes are typically kind of heavy and clunky, possibly with solid tires that don't blow out but transmit every bump in the road to you

• bikeshare bikes are usually one-size-fits-all, which I guess is fine if you're the perfectly average size, but they're always too small for me; an improperly-sized bike is harder to ride and can create more strain on your body

And of course you can subtract maintenance costs, I'll pull 50€ out of my ass as a yearly number for that.