I've always felt that:
1CP = 1 US Penny
1SP = 1 US Dime
1GP = 1 US Dollar
1EP = 10 US Dollars (when they were used in D&D previously)
1PP = 100 US Dollars
1AD = 1,000 US Dollars
You are off by a factor of about 50.
1CP = 50 cents
1SP = 5 US Dollars
1GP = 50 US Dollars
1EP = 500 US Dollars
1PP = 5,000 US Dollars
1AD = 50,000 US Dollars
Food
Meal, common 2 sp = $10
Meal, feast 5 gp = $250
Drink
Ale, pitcher 2 sp = $10
Wine, bottle 5 gp = $250
Inn stay (per day)
Typical room 5 sp = $25
Luxury room 2 gp = $100
Backpack (empty) 2 gp = $100
Bedroll 1 sp = $5
Flint and steel 1 gp = $50
Pouch, belt (empty) 1 gp = $50
Rations, trail (10 days) 5 gp = $250 (dried food is $7 per meal or $210 for 10 days)
Rope, hempen (50 ft.) 1 gp = $50
Waterskin 1 gp = $50
Climber’s kit 2 gp = $100
Grappling hook 1 gp = $50
Hammer 5 sp = $25
Pitons (10) 5 sp = $25
Fine clothing 30 gp = $1,500
Tent 10 gp = $500
Riding horse* 75 gp = $3,750 (i.e. motorcycle)
Granted, some of these prices are way off kilter, but that's just because whomever wrote up the 4E prices didn't know jack about economics.
But the baseline that I use is the food and room prices.
The 3E prices were much closer to 1 GP = $100, but 4E prices are cheaper.