I know quite a bit about laser engravers if you have questions.
Well, more about the lasers they use (different flavors of CO2).
There is a wide range, from the several hundred dollar Chinese units which may or may not arrive completely working and may only last a few weeks (think of these as the Harbor Freight laser engravers). Then there are the ones like Epilog, which are tens of thousands of dollars but are generally well made and have a large work area and good support. The Festool of laser engravers.
The cheapest ones use a small (usually 25 watts or so) sealed glass tube high voltage DC excited CO2 laser with a glass water cooling jacket. These can be long lasting if made well (there were some medical lasers I used to have which had a 55 watt hard sealed glass tube co2 laser which was still putting out 50 watts after 22 years!). It is doubtful the $200 laser engraver would have a long lasting tube...expect about 6 months max out of the tube...although it is replaceable.
The expensive lasers have something like a Synrad Firestar RF excited sealed metal tube laser. The smaller ones of these (under 60 watts) are usually air cooled and fairly compact (maybe 20 inches long). They will last decades under light use. I have a 25 watt Firestar made in 2002 that is putting out 27.8 watts still. The laser itself is about $3000 to $9,000 new from Synrad, so this is why these type of laser engravers don't sell for $999.
There are places that will recharge Synrad laser tubes somewhat cheaper than Synrad does (Synrad charges A LOT to recharge). I think ebay has some advertisements on these recharge places. Most of the smaller RF excited metal tube CO2 lasers have the RF supply built in, although the really big ones (100 to 400 watt) it is usually a separate rack mount thing.
None of these will really cut metal....you need gas assist and 200+ watts or more. They can engrave anodized aluminum quite well though.
If you want to cut thin steel, I have used a small, cereal box size IPG laser which puts out 10 kilowatt pulses and can punch through about razor blade thickness material. It is a much shorter wavelength (1064nm vs the 10,600nm of CO2). Very eye dangerous as well...CO2 is dangerous but the beam is stopped by most (almost all?) plastic safety goggles...well, for awhile. If your vision through the goggles starts looking like a Dali painting, move out of the beam quickly.
