The only differentiation I can see is the really expensive ones can scan the tiny 2d codes that are silkscreened on some ICs, and the cheap ones are limited to about the same resolution that a standard consumer printer can print a barcode at. Unless you have some very specialized requirements, you should be good with just about any cheap barcode scanner.
An important thing for secondhand ones is to download the manual; it will contain a set of configuration barcodes so you can factory reset it, turn off beeping, etc.
I'm surprised by how simple and easy to understand the data serialisation is on some bits of hardware as in this case.
For general tinkering and exploring I picked up the Digilent Analog Explorer 2 with the Ham Radio bundle[1]. They had a coupon deal where 'hamradioworkbench2018' would unlock a $100 discount. Not sure if that still works. While it is a USB scope (so you are dependent on your PC/Laptop for a display) it includes some other useful bench top tools.
Used scopes in the 100 - 200 Mhz range from the 90's are often pretty inexpensive and can usually be calibrated and repaired. This is especially true of the Tektronix 465 and 475 series which were sold in huge numbers. While not as crisp as a digital scope they work well and can be found (at least in the Bay Area) for $50 - $100. About double that on ebay.
The Rigol folks really pushed the price point hard and their DS1054 and DS1102D series are fairly common and inexpensive at $300 - $500.
Scrounge around HAMFests or surplus liquidators and you can often find a deal if you know what you want.
[1] https://store.digilentinc.com/ham-radio-workbench-bundle/
I was kinda hoping that this would be someone porting Nerves to run on the barcode scanner itself; quite a few of these scanners actually have reasonably-powerful ARM cores (especially once you get into the 2D scanners).
For RS232 any 'scope is going to be fine, even a chinese clone knockoff or an ancient second hand scope.
It's nice to see that someone else came up with this idea, executed it so well.
Great writeup with detail!
I'd like to do a database of products purchase, purchase date, price paid, scan a barcode and mark it as consumed, and calculate typical consumption rate of the products.
I will keep things pretty simple, either a sqlite database that stays local or a LAMP setup so I've got access to an inventory list at the store along with "price check" functionality.
I was thinking of something similar, but mostly as an inventory + expiration tracking system, because we often forget what we have in the fridge and cabinets. I love the integration with Wunderlist for adding to the shopping list as well!
