If you can hold out until Fall, I typically see a lot of junk boats on Craigslist listed for a few hundred dollars.... they have been sitting in someones yard for years and they finally just want it gone...and often they are sitting on a decent trailer that just needs a light kit and new tires.
I picked up a very beefy dual axle trailer with a junk boat for $500, stripped the boat of all useful hardware and then sold the hull as a project for $100. I now have a Rhodes 22 sailboat on that trailer. A local welding shop can help you put tangs on it to attach the bunks and that will cost you less than $100.
Something to consider.... I don't know if this is true where you live or not but.... in Virginia, a dual axle trailer needs an annual inspection (PITA) and it must have breaks.... not true for a single axle trailer. The Rhodes is a 4000# displacement boat so I'm glad to have the breaks.... but you may have a different calculus for a Mac 25. The Mac 25 has a real keel (not water ballast like the 26C) so you may also like the security of breaks....????