What is the best way to thank a system administrator?

I work in the regional branch of a Moscow organization as a system administrator. The post sounds loudly "Head of the unified service of information technologies in the region", but in fact the usual administration of two networks, telephony. Our staff is very diverse with more than 100 people. In the IT field at the company, I am alone against this hordes. Many working in a similar position, faced with the fact that some employees ask for help with a home computer. Reinstall Windows, install an antivirus, some other software, upload new maps to a GPS navigator, etc. Since we have a provincial city, there are requests to download something on the Internet, the latest KVN record, some movie, programs from file-sharing networks. Everything happens, from pressing the “magic button” to recovering data from flash drives and screws. Someone from whom I helped say "thank you", someone believes that the administrator does not feed, just let me dig deeper into someone else's laptop in search of the causes of "brakes" or an exotic virus. Requests are different, and thanks for them are either verbal or “negative”. These people are just colleagues, except for work, often, nothing connects us.
So, I would like to ask the habrasociety, in what ways do you accept gratitude for solving personal problems of IT employees? Honestly, it’s not very motivating to do something for a person who will simply say “thank you”, saving you 500-700 rubles for calling a computer master at home. I could have done work affairs for the time spent, or something useful in the end. How do you think?