If you are wanting to spend 250$, you might look into the xtracycle to see if it would fit your needs. Its a conversion kit that moves your back wheel 15 inches back, and creates a large rack space. Much more comfortable to ride than pulling a trailer. Of course, it doesn't just pop on and off like a trailer.

Anyway, you might look into it, its just another option for hauling on your bike, and one that is pretty practical for a lot of people, particularly if they have a second bike that they would convert.

http://www.xtracycle.com

Also, bike trailers can be found used pretty easily, and even the 'person carrying' ones switch easily to 'stuff carrying'.

peace,
sam