I'm a solo traveler on a pretty strict budget and Hotel Leto was the cheapest place I could find in all of Nafplio and after staying for one night I thought it wasn't a bad choice in the end. It cost me 30 Euros including breakfast for a double room with ensuite bathroom, A/C, TV, minibar and street-side balcony. The room and bathroom were very clean and there was wifi but it did not reach my room. The breakfast was very simple being some bread & spreads, yogurt and apricot as well as an orange juice and tea/coffee.
As for the location, Hotel Leto was along the side of the old town (opposite the port). It is merely a 30 second walk to where all the restaurants and bars are, yet perfectly placed for a quiet night's sleep. George (who I suspect is the owner), along with the rest of the staff were very friendly and helpful with whatever queries I had.
Overall I enjoyed my one night's stay and would definitely return if I was heading back to Nafplio. I searched high and low for budget hotels in the old town and this is the best I could find - and I'm happy I went! Thanks.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.