Cost of digging out and pouring basement floor.

That is like saying how much does a house cost.

Not to ask the obvious, but have you looked in your Yellow Pages and called a local concrete contractor for a bid? Maybe two or three bids will give you a good idea of what they charge.

Mike wrote:

do you want to add more headroom?

I'd guess $5000 to $10,000. The concrete alone is close to 1k. How is the existing concrete and dirt going to be removed? Dumped? You can probably find someone to take the clean fill for free, but hauling it to a spot cost hundreds. Same with the breaking up and hauling out of the basement. Very labor intensive. That is a lot of wheelbarrows of dirt. If it is not a walkout, add another couple of grand for the bucket brigade.

Since you are in Denver you should consider a passive radon system under your slab if you replace it. Very low cost addition if you are replacing the slab.

underslab vapor barrier and interior french drain since your ripping it up anyway

Like the others said, Its about 13.5 yards of concrete, so depending on what the cost is per yard and what mix you want, the concrete alone can cost from $1100-1500. Then you need a pump unless you have access. Here a pump is about $500-800 that amount. A sub will charge prob. about $7K-10K for the job.

Some money saving advice. Take the concrete out yourself. Rent a electric hammer and a couple of guys you see at the Home Depot hanging out. Bust it all up, get rid of it and remove 3" of dirt. Buy your own vapor barrier or 'visqueen' and drains if need be. Not sure how wet it is there. We make most of our money on jobs like this doing the removal and disposal, mainly because we hate it and its a pain in the ass.