Yes, there are connectivity costs to use our NB IoT smart padlocks on local telecommunication companies mobile networks. The locks connect to mobile networks like mobile phones do. But unlike mobile phones, the smart padlocks use very little data - on average less than 5-10 MB a month. For example unlock commands and data retrievals (such as for the live audit) are around 8-10 bytes on average.This means we can take advantage of the lowest data plans offered by local mobile network operators for utilising their NB IoT networks. For example in some European countries you can pay a one-time fee of 10 Euros when you purchase our smart padlock and receive a data flat rate of 500MB to use over 10 years on Deutsche Telekom's NB IoT network - click here to see more. Thats right 10 Euros for 10 years. If you only use your smartlock a few times a day, then this plan may last for 5-10 years.  Prices depend on different carriers in different countries. Please check with your local carrier or our distributors for pricing, or send us an email info@digitalkeys.io if you would like to know more.