Note: Sadly, the Ratchada Saturday Night Market is no more. The land it used is slated for development and there is no other suitable space nearby. If you were interested in this market, the Railroad Market is very similar.
Every Saturday night, many Bangkok residents flock to what can only be described as a good old fashioned swap meet. As the sun starts to set, cars, trucks and vans jockey for the best spots to set up shop in the vacant lot on the corner of Ratchadapisek and Ladprao Roads, next to the big subway parking garage. By the time it gets dark, the aisles between the stalls are packed with people out for a look.
The big crowd at the Ratchada Saturday Night Market (in its old location)
There's no telling what you can find at the Saturday night market, although "junk" might be the best overall description. Much of what's on offer are the contents of people's garages, attics, or the back of the van, although you will find some stalls selling new items, from fake watches to cheap imports from China (okay, same thing, but you know what I mean).
There are a lot of car parts on sale; new, used and otherwise; as well as many classic motorbikes and a few older cars on show and sale. But that isn't all you'll find here. I've seen pets, sun glasses, clocks, antique telephones, and just about everything else on offer.
I'd class a lot of the "antiques" as kitsch rather than valued items. They seem like things that might be fun to have - adding a bit of whimsy to the decor - but I have yet to see anything I had to have.
As with any shopping in Bangkok, you want to be sure you know you're doing if shopping for "antiques" at the Ratchada market. Are those old Beatles posters real? I don't know, and if the guy is asking 100 Baht (2.60 USD) for them I might not care. But if he wants 1,000 Baht (25.97 USD) for a poster, I'd want to know for sure it was a real vintage item.
In addition to all the stuff, you'll of course find lots of food on offer in the market. There's even one or two small, temporary bars that set up shop for the night.
For most visitors, the Saturday night market is more of a "sight" than shopping destination. You will probably need to know a bit of Thai, or bring a Thai friend with you, if you want to do some serious shopping here. The railroad market offers a similar feeling and products, in a slightly less claustrophobic atmosphere.