You are right that technology has advanced quite a bit in a short time. There are some good digital scopes available that should work well. The older Wraiths are cheaper, but have less resolution.
I have either tried or looked through a variety of night vision devices, and for digital I like the ATN 4k Pro. I started with the 3-14x model and later got the 5-20x one. Both are good, but also they are priced higher than the old model Wraiths, but they have good resolution and features.
As to a thermal monocular, I got the AGM TM-10 with 256 resolution. It is not as good as higher priced 384 models, but it works for me at closer ranges, and I got it on sale for slightly under $500. It is very usable for my intended use of hog hunting over feeders at 100 yards and less, or close range calling. I have spotted deer much further. Basically you just need to know an animal is out there and then switch to a rifle scope for better ID.
As to the cheapest digital night vision available, there are units available on Ebay and Amazon that attach to the back of a daytime scope. I built a home-made outfit of similar design for about $230 (at the time), but you can get some fairly good looking ones for $200 plus. I have no experience with them but see no reason why they wouldn’t work well enough. A good 850nm illuminator is needed.
If you want to see the home-made and digital units in operation, as well as IR illiminators, then go to my Youtube channel at: 6mm064.
Here are a couple of examples of low cost digital devices to fit behind a daytime scope. I have no experience with either, but if they work for you then the price is well worth it. I think they are returnable. A good illuminator will be as important.
Infrared technology: Increase the range and accuracy. Our high-power 850nm infrared illuminator allows you to easily reset to zero on any target, up to 300+ yards! Applicable gun types: rifle, shotgun, crossbow.
www.ebay.com
Model: NVS30. Dimension: 155*80*46mm. Sleeve Diameter: <48mm (universal Adaptor). Eye Relief: 30mm. LENs Size: 16mm. Magnifying Power: 4x - 14x.
www.ebay.com