Scamps, Casitas, virtually all molded fiberglass trailers generally sell VERY quickly if they are even close to fairly priced.
You need to check the various websites, including this one, for announcements of trailers for sale
, then be ready to act quickly. Also, be ready to travel a considerable distance, especially if you are in a hurry. Do not wait until you find your trailer to figure out how you will finance it, plenty of folks will also be interested in it, with cash in hand.
The prices will also be higher than you think, compared to a new unit - this is good, once you have a trailer, as they do not depreciate very quickly, but it is a shock to many new shoppers. One obvious reason for this is the longevity of molded fiberglass trailers if they are reasonable maintained, and a second reason is that every current manufacturer builds to order, often with a 3, 6, 9 month lead time from placing the order to receiving the trailer. If you need/want one sooner, you must buy used.
All this being said, you must use caution when you find one on Craigslist or ebay. Because they are in demand, and demand a very decent price, they are the subject of quite a few scam artists. If the deal seems too good to be true, or the trailer is across the country from you, use a great deal of caution. Post the listing you find here on this forum and several experienced folks here will give you their opinion and suggest how to proceed with caution. You must keep in mind, though, that if it is a legitamate listing, speed is also required - catch 22.
Good luck, and Welcome.