Ancient Egypt didn't have a monetary system until 2000 years after the pyramid's construction so it is probably better to use work hours and the cost of employing workers as a comparison, especially because the value of today's money is heavily warped compared to a barter system.
How many people worked on the Great Pyramid?
Excavation of the pyramid town south of the Sphinx have revealed galleries that could house about 4000 workers. At the start of the construction however it is likely that several more thousand workers were hired to clear the perimeter of sand and smooth the bedrock, and complete the first few layers of the pyramid.
To provide for those workers a brigade of tailors, bakers, sandal- and wig makers, butchers, and many other people that transported or provided goods and helped logistically.
Workers were well cared for, and received benefits such as:
Medial care, tax exemptions, cloths and housing, food for their families, usually 1 day off per week (5 day weeks), beer (which was a very common drink with low alcohol content), beef (cows had to be imported from other parts of the country), wigs, makeup, all kinds of fruit and vegetables and of course bread, amongst other things.
All in all most of the time about 6000-8000 people worked directly or indirectly on the monument's construction.
How long did it take?
The Great Pyramid was not the only thing being constructed by those workers. A mortuary temple and a valley temple with a harbor had to be built with a causeway of several hundred meters connecting them. In addition 3 Queen's Pyramids, a satellite pyramid, 12 mastabas that were later joined and expanded to 8 twin-mastabas and giant perimeter walls had to be built as well.
The majority of stones was local limestone that came from the east side of the plateau, only a few hundred meters away from the pyramid. Under 1% was hardstone such as basalt and granite that was imported from upper Egypt and the rest, the white limestone was imported from Tura in the north-east.
In total about 2.5 million m³ of local limestone had to be quarried and transported. In contrast to popular believe the vast majority of those stones were not neatly cut, square blocks but stones of all sizes and shapes. We know this because Vyse blasted a hole into the south side of the pyramid.
To cut (mostly stone tools were used) and transport 1m³ of the local stone approximately 40-80 work hours had to be spent depending on the stone and location (2 people quarrying for a day, 2 trips á 1 hour with a 10 man team to transport).
Including the other stones it would have taken 150,000,000-200,000,000 work hours to complete the pyramid and the adjacent buildings.
We don't know how many people only worked seasonally and how many all year, so completing the pyramid would have taken between 10 and 20 years with an average of 5000 workers (assuming 10 hour days, 150 or 300 days of work a year).
How much did it cost compared to today?
Only a few percent of the workers had to be highly skilled (architects, stonemasons, foremen, etc.) but most workers were well cared for (even by today's standards).
Since it was a royal project the Pharaoh didn't have to pay for land and most resources but they still have a value. To translate that value to modern money is difficult however since goods like grain can not be stored and easily exchanged as money on a bank account can.
But to put a price on it: Assuming 5% of the workers were highly paid: 50$/h and the rest moderately well: 20$/h it would cost around 5 billion dollars to pay for ~200 million construction work hours and the people providing for them.