First of all; not one supermarket sells a decent bicycle, so shopping for a fold-up in your local mart is a very bad idea. Bikes might be cheap, but the quality is nothing more than plain crap. Sales staff are not knowledgeable and after-service does not existed. Don’t do it!
Unless you’re an expert, it’s better not to buy your folding bike from the classifieds in the newspaper or online website. Chains, sprockets and wheels can be worn out, without you noticing it. The replacement of these parts can be a costly affair. Even is the bike is new-ish, the warranty will go void as you’re not the original owner.
3) Pop-up Shops
Pop-up shops are the latest fashion in the retail environment. They’re often an ideal way to get rid of some extra clothing stock or to showcase some arty stuff, but are never suitable for a bicycle store. A bicycle does need some after-sales service, so chances are the shop will be closed by the time your bike needs a service. They generally don’t even bother with a workshop. As it is a temporarily shop, the sales guy is often not knowledgeable nor interested.
4) Certain Online Shops
This is a difficult one; because some online shops are really great, others are not!
Some online shops are downright scary; no secure payment and/or even a decent choice.
But a good online shop can be a great way to purchase a folding bike, as long as they are from a reputable distributor/shop. Make sure they have secure payment and decent shipping options. Also make sure they give the right warranty (Dahon gives a 5 year frame warranty!).
5) Cheap Chinese ImportsAs folding bikes are getting more popular, some individuals import a container full of cheap fold-ups. They probably also import shoes, kayaks or t’shirts. They often sell directly to the public via the online classifieds websites. These bikes are cheap, but the quality is ‘not great’. They also don’t have any technical back-up knowledge, don’t offer any warranty and will probably discontinue after selling their first load. Bikes will also be sold under a unknown brand. Beware!