I recently purchased a used, 1981 Tomos Silver Bullet moped for my son who's away at college. I rode it for a while before giving it to him and must confess I've been bitten by the moped bug!
Back in the late 1970's, I bought a Honda Express for zipping around town (New Orleans at the time) -- much cheaper than a second car! An Express wasn't a true moped (it didn't have pedals), it could only go about 18 mph, and it was legally considered a motorcycle. That meant it needed a title, a license plate, registration, etc. Mopeds, on the other hand, were legally considered bicycles at the time and needed no titles, registration, etc.
Things have since changed -- but not for the better! Now, practically every state has conflicting and confusing legislation concerning mopeds. Most now require title and registration.
The problem with used mopeds is that most were imported at a time when titles and registration were not required. That means that most used mopeds from the 1980's and earlier simply do NOT have a title and never have. Although these bikes are capable of many years of fine riding, you're likely going to have a challenge getting them registered.
Some states will grant you a title with a bill of sale; some exempt older vehicles; some unfortunately aren't quite sure exactly what to do. I ended out having to purchase a surity bond and get two appraisals in order to get my 1981 Silver Bullet registered in Texas. It took me two months and SIX trips to the DMV (every time bringing everything they had asked for the previous time) -- and then they charged me a penalty because it took so long!
My son actually goes to school in Louisiana. After haggling with the Texas DMV, I thought I'd give Lousiana a try. Much worse -- after many many calls to the Louisiana DMV, no one could figure out how to get it registered at all! I finally decided to register it in Texas -- since I could then transfer the completed registration to Louisiana!
Still, if you're considering purchasing a used moped, don't let this scare you away -- just be aware that it may take a little work to get your bike registered! You may want to check with your DMV just to get an idea of what's going to be required in case you must register your moped.
So, if registering a title-less used moped may be difficult, then why buy used? Well, you'll find that prices on used bikes are very reasonable; these bikes are simple and solid and will last quite a long time.
In fact, you may find that shipping a used bike from a seller may be a large part of your cost! Interstate shipping may run you from $150 to $250 -- sometimes more than the cost of a used moped!
One way around this is to search for local used bikes -- which would cost you only a tank of gas or so to go and pick up! I've created a list of currently available used mopeds and moped accessories and have grouped them by state. This list gets updated every single day so it'll always have the most current information I can find!