Roughly how much to replace the following in a 98 Ford Explorer?

Needs 2 o2 sensors dot 3 overflow needs to be replaced and a head gasket.

The parts are cheap, but the labor, watch out.

That would depend on the cost of labor in your area. If you live in New York or San Francisco, for example, it will be a lot more expensive than if you live in Lubbock or Sioux Falls. The cost also depends on whether you plan on paying retail; price for the parts at the repair shop or whether you'll be shopping on the internet. Hint: some shops either won't install customer-provided parts, or they won't guarantee their work if they do install them. Bottom line, since we have next to zero useful information, it's going to cost somewhere between $1300 and $3000, probably more than that old heap is worth.

Roughly $2000

Hi so the real issue is about a worn out old engine.

About $350000

Since you didn't indicate your geographic location, it's hard to say how much the labor cost would be for the repairs. The parts should be competitively price for most areas, but the labor per hour would be significantly different in states like California, New York, Florida or New Jersey versus states like Indiana, Utah or Ohio. The sensors would be an easy repair, but that head gasket repair would be very involved. I'd estimate anywhere from $1,500 to $2,500 for everything.

Between 1500 and 2500 $