https://www.amazon.com/gp/product/B00ICTH8AQ/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

I've got a SPARK CORE.  It's probably top of the line as far as Gen 1 goes IMO.  But I used to work on/with Gen3 binos for a living and while the CORE has great resolution it's light amplification sucks, and it has about 5 degrees less FOV than newer Gen night vision.  5 degrees doesn't sound like much on paper but in practice it's a huge.  Save up the same 500ish the CORE costs a few times over and at least go Gen 2+.

You'll have to factor in the cost of a good IR Illumination with the cost of the CORE as the built in IR illumination is ok at across the room distances you need more for further than that.

If you have any specific questions about the CORE let me know and I'll answer as best I can.  I've had one for about 2 years now.

Spark Core is probably the best Gen1. You can't get new Gen2 under $1000. That settles the OP question.

Now, it costs about $750-ish... If you save up 4 times that, you will get $3000. For that much, you can get a proper high-gain NV device.

Then you will go from a system gain of around 100x to a system gain of around 5000x to 7000x.

Think about that. Four times the price, Fifty to Seventy times the performance.

So if you save up, you can have 70 times the performance for just 4 times the cost.

What do you want to do?

Hold out for a used set of PVS7's from the equipment exchange here on arfcom they have been coming down in price and you could get a solid unit for $1000-1400 just by watching the sales board for a few weeks.

They will be gen 3 and work great and if/when you decide to upgrade you can turn them back around to someone else for right about what youre paid in for.

Ive bought gen2 units for half that.

This is solid advice

The input I have on the Spark CORE is that it is better than having no NV at all.

I have been pleased with it as far as indoor use - it gives a tremendous advantage with an IR illuminator.  Without an IR illuminator, it is little better than the naked eye.

Outdoor use it is certainly still better than nothing when you have an IR illuminator.  Unfortunately, this increases the equipment you have to carry and increases your visible signature.

I am not intending to save up and get a Gen2 or Gen3 unit unless I run out of other gun stuff to spend money on, so for me the Spark is good.  I'm just happy I can see in the dark.

Yup. If you are dealing with folks with no NV it can give an advanatge if you use it right. Against anyone else thats another story.

Save to 1,000 and buy a new gen2+ or 1,000-1,500 and buy an lightly used gen 3. The darker it gets the better NODs you'll need to see without supplemental IR. The difference between gen1 and 2 is huge, the difference between gen 2 and 3 are closer, but modern gen 3 blows the doors off both in very dark conditions.

Use financing on a better unit now.  Otherwise it will take too long to buy your eventual Gen 3 purchase and you will have wasted a bunch of time. Better to waste money on financing than time.