My first thought: you're going to have to increase your budget. I suspect that there are few string trimmers that are worth a darn for serious use at the $200 price point (none spring to mind), and can assure you that NOTHING at the $200 price point will run a blade acceptably.

I know of a few people who have put blades on Echo SRM260 (26cc, both cable and solid shaft versions) and have accomplished a lot of brushing. But it was slow, and required a gentle touch to keep the machine in its power band. I know that my SRM260 will lose RPM in heavy grass with standard-length .095 line, and I can't imagine it wanting to run a blade on woody brush.

What you will need, frankly, is a 30cc+ machine. Stihl's models are the ones I'm most familiar with, and you'd want to look at the FS250 and FS350 as your best choices for blade use on brush and small saplings; an FS130 would probably work, though you won't save that much coin over the FS250. I've got an FS200 (36cc non-EPA version of the 40cc EPA-friendly FS250), and run a tri-blade on it almost exclusively. It is enough machine to handle brush duty, yet light and nimble enough to run a line head in heavy grass, too.

The unfortunate truth is that saplings require a LOT more guts to a trimmer/brushcutter than is required for grass and soft vines. Stouter driveshafts and clutches, coupled with much more powerful engines, are simply required. You will abuse/wear out a smaller machine in short order, and have a miserable time using it in the meantime, if you opt for something in the $200 range (i.e. Echo SRM210, 230, Stihl FS55).

The other problem that you're going to find is that these truly blade-capable machines, being more specialized and much more expensive, tend to be purchased by people who actually need them, so you see fewer of them on the used market than you do with

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