But what common hard liquors are nationally distinctive?
For example, in the case of báijiǔ, one of the inexpensive varieties is èrguōtóu, a clear sorghum liquor. One of the most popular brands is Red Star (红星, hóng xīng), which comes in a variety of strengths up to 112 proof:
I read that it's available for as little as $1.50 per 100mL bottle.*
Then there's Russian vodka, which I'm told is produced by thousands of distilleries all over the country, some of which is very cheap indeed. This discussion on bad vodka led me to a brand called Охта, from the ЛИВИЗ distillery in St. Petersburg. I snagged a photo of the label from a post on an auction site in Russia which lists the completed auction as having gone for 15 rubles plus 30 rubles shipping, or a total of 45 rubles ($1.50) for the liter bottle.
As a useful side-benefit, using inexpensive hard liquor will reduce our research expenses. We should highlight this in our grant proposal.
Brazil has cachaça, the United States has bourbon, Latin America has aguardiente, the Balkans have rakia (of which slivovitz is a variety made from plums). Korea has soju, Japan has shōchū, and Southeast Asia has arrack, which is distinct from Middle Eastern arak.
Anyway, you get the idea.
Edit to add: This site has Cachaça 51 Pirassununga (one of the best selling brands in Brazil), 78 proof, for R$5.95 a 965mL bottle. That's about $3.20 for the bottle, or $3.32 a liter.
It also comes in aluminum cans:
*I overestimated the cost of èrguōtóu. http://www.cntvs.com/product/1663/081031/25907/ has the stronger 65% (130 proof) for 12 yuan ($1.75) per 500mL bottle, or around $3.50/liter.