Another vote for Penn State Industries' "Benjamin's Best" line of economy turning tools. They're of great quality for the price.
Never heard of Simmonds.
Suggestion: Don't buy a set of tools. Buy individual tools as you need them. For instance, most sets come with a skew, but using a skew takes a more advanced skill level...You can easily live without it. For turning pens you can get by pretty well with a spindle gouge and a roughing gouge. A scraper or two can come in pretty handy. Used tools are fine but remember than turning tools have a limited amount of "life" in them...Sharpen them enough times and they eventually don't have enough steel to sharpen.
I'd spend the real money on a means of sharpening your tools. Even the best tools are useless after an hour of turning if you can't properly sharpen them. Heck, they aren't even sold sharp and ready to use. For this you need either an 8" bench grinder with a friable wheel and some sort of jig (Wolverine, PSI, home-made)...Or something along the lines of a Tormek. As a newbie turner you'll soon be frustrated to the point of quitting if you aren't able to get your tools properly sharpened. Your best bet is to find an experienced turner in your area and spend a few hours with them in their shop watching, learning and taking notes.
You'll see a lot of turners saying that the lathe itself is one of the more insignificant investments you'll make when it comes to woodturning. Add up the chucks, mandrels, tools, sharpening, sanding, glue, protective equipment and other necessities and it'll quickly add up to a heck of a lot more than a good midi lathe.