G.G.
I got an InStep on Amazon for around $80-$85 and it's almost perfect. We use it for leisurely rides to the park about 1 mile away and as a stroller at times. My only complaint is that-never having seen the inside of a bike trailer before-I assumed it would have a hard seat and the one I bought did not. It was more of a sling-style seat. Our toddler has never made issue of it, so neither have I.
I would check Amazon and read some of the customer reviews. If you're not a serious cyclist, something under $100-$150 should be easy to find.