Monitor is going to need a rebuild. Odds are it’s a Sanyo 20ez monitor which are work horses once they are gone through fixed and dialed in. They are a pain in the ass to work on through.

What sort of cabinet is it in?

For me this would make a difference if it’s a Nintendo cabinet or some kind of conversation.

It could be a board issue, rather than a monitor issue. It depends on what "bugs out" means.

It is certainly worth pursuing.
Has he offered any pics or thrown out any price whatsoever?

https://www.arcade-museum.com/game_detail.php?game_id=8624

https://www.arcade-museum.com/game_detail.php?game_id=9913

For 200 bucks I dont see how you could go wrong grabbing it. Really fun game especially with two people.

OP said Super Mario, which would be the harder arcade version of the NES game. Definitely worth grabbing.

That first one is a standard Mario Brothers which is a wide body.
I doubt it's going to be that as he said Super Mario Brothers.

Most likely something like the second, a players choice 10 or some other cabinet or perhaps a conversion.

I would guess a VS. cab with a Super Mario board and marquee. Let's see some pix!

Sanyo monitors aren’t hard to repair. It’s usually just a good ole “cap job”. Sometimes you’ll need an RU-2 diode for vertical collapse. The hard thing is that the chassis doesn’t remove all the way from the tube so you have limited work space. If by “bugs out” the seller means something like loss of vertical hold, there’s a bipolar cap (maybe 2.2uF 25V? ((I think it’s C201??)) been a while since I’ve worked on one) that’s the culprit. Common issue. Surprisingly the flybacks and horizontal circuits were seldom and issue. Nintendo CPUs were actually pretty reliable. I can’t remember having to repair very many and I’m basing all this as a kid that grew up in the 80s when my pops probably had 200 Nintendo cabinets on the route.

Sometimes folks automatically refer to the game name as "super mario brothers" regardless of what version it actually is, since that's generally the most well known name for the game series. Even the movie was called "super mario brothers". So, if the game's name came from an unknowledgeable owner, there's a possibility that it could be one of the other titles.

LOL, post some pics when you get a chance to dig it out of there.

Mario Bros marquee has the heads of mario and luigi on each side. Vs Super Mario Bros marquee looks like a level of super mario bros and are usually extremely faded in color. Nintendo Vs upright cabs are typically converted Donkey Kong, Popeye, Donkey Kong Jr., Mario Bros cabinets. If its grey and a slightly different profile cab with a different style coin door, it is a dedicated vs cab but these are far far less common. In fully working order and decent cosmetic condition, Vs machines go for $400-$600. $200 would be a good deal. The monitor likely needs rebuilt, but you might get lucky and it only needs to be adjusted.

Fix the monitor, it's not difficult and if you want, there's plenty of people that will fix it for you. If you swap it out, you're not playing Super Mario Bros, you're playing a delayed version of SMB that will look worse.

If you insist on swapping to an LCD, hang onto the monitor, so that the next person can fix it and put it back in.

Could be super breakout or something

That's not bad. I've seen a lot worse.

Thanks for sharing

I would buy it instantly if it were near me.

So would I. Most of those VS cabs are in similar shape. Doesn’t look to have any water damage. A Brad nailer and you’re back in business. Easy sell down the road for a profit too.