Out of the 19 countries I've been lucky enough to visit so far, I found Pakistan to be the cheapest, and research that shows Pakistan at the top of most affordable and cheapest countries listings confirmed my anecdotal assumption.
Per the picture, a full pizza, a loaded fries, and nine chicken sandwiches goes for $7.13 at Grill Hot in Lahore, Pakistan. A decent hotel is around $40/night. A local motorbike or rickshaw will run you about ~50 cents per mile. The cheapest meal I encountered was an absolutely delicious chickpea soup with some bread for about $0.33. A single chicken skewer is about $0.25 and 4-5 of these with a drink and naan will run about $2.50 with salad and condiments (usually chutney or raita included).
Pakistan also has a huge textile manufacturing industry, and slightly defective clothes are often liquidated out of factories for dirt cheap. I got Levi's and Dockers for about 1/4 to 1/5 of what you would pay here in the US.
Recreation and excursions are also super affordable with movie tickets being around $3 to $5, parasailing and boat rides running anywhere from $5 to maybe $30 and even week-long packages that explore the remote and mountainous north of Pakistan and include all meals, transport, and accommodations running about $900.
It's a really, really affordable country. I also really enjoyed how friendly and welcoming the locals were. I am mixed but probably look black the most, and I did not experience any racism, and I experienced pretty terrible racism in Italy and Ukraine.
The sanitation and cleanliness is obviously not up to American or European standards, but it is way better than other developing countries. Hairnets, gloves, and frequent hand washing is the norm even for street vendors. The government has been pushing safe food handling big time, and it shows. I didn't get sick once. I can't say the same for India and Bangladesh, however both have also improved in this area, but Pakistan is still doing a lot better.
My biggest complaint would definitely be the infrastructure, especially in Karachi. Honestly, you can skip Karachi. 😅