Sorry, I do not know what the Girls earn, but I do know that the Ladies that send out Daily / Hourly Chat requests are making a living from these Dating sites. Women pay Nothing to be on the web site. I heard one young lady when I was in Ukraine (2013) say that she answered an AD, reported for an interview, and was told that she would have her photographs taken by a professional photographer. She was told that she would be paid for Chats by the minute, and for Letters that men sent to her.
The young woman thought she was signing up to become a member ( to find a Husband ), but quickly realized that she was just being hired to just Distract male members.
Young ladies will tell you that these Dating sites are just a Job for them. $100 USD ( = 2200 UAH) In Ukraine is a lot of money, some Familes live off $2400 UAH PER MONTH.
It is cheaper to visit Ukraine than it is to keep charging your credit card to be able to Chat, read and write Letters, and request personal phone calls.
It seems that most mid to late 20's Ladies do not speak much English, but many Do understand English. Hire a Trustworthy Interpreter / Guide, and these interpreters can arrange several first meetings and Dates for you ( in real life, not through a Dozen fruitless Letters).
Avoid the expensive Tours, $6000.00 is not really worth 10/10 days and nights, especially when you can rent an entire apartment for less than half of what you are charged for a small Hotel room. Just Remember that your Dollar is worth about 20-22 UAH IN THEIR country, and a 450 UAH / night Hotel or apartment is actually only about $22.50 USD.
Travel like a Tourist, and you will spend a Ton of Money.
Hire a translator at $15-20.00/ hour, and you will save Hundreds of USD. Ukraine is really no Different from other East or West Euro countries. Prague is also about $20:1.00 in the currency exchange.
If you are not a Traveler, it might be Best if you just stay home, but if you are Travel Savy, then explore Eastern Europe...