In my previous job, I'd head to the Koramangala of Bangalore a few times a year. Several of the bars there were offering hotdesking packages, at your choice of ~$20, $30 or $40 per month. All of them got you a guaranteed table near a power socket with wifi every day of the month, with officially issued invoice to that effect. Whatever your monthly subscription, you then got that exact amount to spend on food + drink at the bar!

Assuming you'll be attracting digital nomads who are able to expense co-working spaces but not refreshments, could be worth offering something similar