I have a ryobi multi-attachment trimmer I got for $75 refurb from Big lots. Then bought $150 in attachments for it. Love it. I bought the tiller, the leaf blower, and this year, I'm going to get the pole saw.
I agree with JD, though. I also have a tiny $45 28cc weedeater from walmart. That thing earns the name 'featherlite'. It's tough as nails, too. I do my trimming with that. (bought the multi for running the attachments) Unfortunately, the carb is unadjustable, and I have to run it on almost 1/8 choke, because the dammed thing is too lean. I'd buy another one without hesitation anyway. I just put a drywall screw in the air filter housing to keep it @ 1/8 choke, and I run it all day. Fuel efficient as all heck. I swear I could run it for 5 min on a shotglass of gas. I usually only go through 2 tanks A SEASON.
Last fall, my neighbor gave me a TORO mult (he couldn't get it to run - came in a box lot at an auction). It fits my attachments too!
I also have 2 running JD trimmers from the '80s, and a Mcculoch. The weedeater is still the best. That cheap $45 weedeater. God as my witness.