It's always fascinating and often amusing to see the many varied ways people have come up with to make espresso without having to actually go out and buy a proper espresso maker. It's easy to assume these are desperate attempts made by people who either can't afford the equipment or are too cheap to go buy it, but I believe this is more in the vane of makers, inventors and designers trying to understand a problem and making a fix. Some efforts are for profit while others are for fun and bragging rights.
I take my hat off to those who have tried. It seems like an easy enough thing to do but in fact a good espresso relies on a fairly narrow set of parameters. The most important mechanical aspects are water temperature and pressure. While it's too late to invent espresso, people are finding lots of weird and wacky ways to brew it. It is actually quite common for someone to come in to the shop looking for various parts from 'real' espresso machines to integrate into their contraptions. Below are a few examples that I found online:
In Italy almost every home has a moka pot (stovetop espresso maker) which is likely the first and most popular commercially produced espresso maker (that's not an espresso maker). While they remain a mainstay the moka pot has the problem of overheating the coffee since it requires the water to be heated above boiling temperature to work. Not ideal but still a great devise that is loved by many. We sell Italian made stainless steel moka pots starting at $48.99.
Today a better choice might be the Aerobie Aeropress. Invented by Alan Adler the famous inventor of the Aerobie flying disk, this simple and easy to use devise is both inexpensive and capable of making very good quasi-espresso. Since the water is heated in a kettle and brew pressure provided by your arm strength the overheating issue is taken care of. While not strictly an espresso maker the user can manipulate the water to coffee ratio and use finely ground coffee to get a pretty dang good shot. We sell these for $31.00 which makes them the best value by a long shot.
The market is full of small handheld 'espresso makers' that use air pressure to much the water through the coffee. You can pump them up like a bike pump or use CO2 cartridges. They are pretty gimmicky but they are popular. Maybe the closest you can get to actual espresso is with The Rok $199.00 (formerly known as Presso). It is in fact a lever operated espresso maker that relies on adding hot water directly before brewing.
Finally, most people want steamed milk on their espresso. We sell a Stovetop Steamer $79.99 that makes true steam totally comparable to an espresso machine. I have had several people tell me the microwave trick works for them (something tells me I am more picky about my steamed milk):