The primers are from the80-90s for sure, I wouldn't be afraid of them but if the powder is the same age, I would be leary of it.
What do the powder containers look like, did you take a picture of them? Curious as to what decade they came from. I would have to smell it and dump it out to look for rust looking particles in it before I would use it. If it's from the same time period of the primers, be careful. If it was properly stored it could be just fine.
The single stage press isn't worth much, maybe $30.00. Not a good press.
The primers by today's standards are $30.00 per thousand, those were $15.95 back in the $1990s. I still have some. They are in a blue box today.
The lead bullets are usually packed in 500 count boxes and cost about $35.00 per full box today.
The Lee Die sets are about $28.00 per set new today.
The Lee Safety beam scale sells for about $30.00 new today.
The Hornady powder measure is a pretty good, accurate measure. It's about $60.00 new today.
Used brass runs anywhere from .03-.06 a piece for the common pistol calibers.
Make sure that Midway tumbler isn't the one that has no feet or air tunnels running under it. Some of those old Midway tumblers were flat on bottom and over heated and caught fire due to no air being able to get up through to cool the motor. Or buy some rubber bumpers and put on the bottom of it to raise it up. The screw on kind.
I'm not going to suggest what you should do here.
I would have to have a better single stage than that one, that one would be useless to me except for punching out primers.
For me it would depend on how many pounds of powder are there, how old it is, and especially what condition it's in. Did you get pics of the powder containers?
You will definitely need a better single stage press. I would look at this deal as I will have to spend another $100.00 on a better single stage press to make it all work for me, then re-evaluate the total cost.
How bad do you want to start reloading.