According to a decree passed by Azarov's government on December 4 that is just now starting to be enforced, foreigners entering Ukraine will now need to provide proof of sufficient funds to enter Ukraine. It is quite a surprise to most of us that the new government has not canceled or modified this decree.
In the text of the decree, "sufficient funds" is defined at 20 times the subsistence level, which is currently set at 1176 UAH per month ($100 USD at the current exchange rate). The resulting monthly sum — 23,520 UAH — is divided by 30 to get a daily amount — 784 UAH — and five extra day amounts — 3920 UAH — are tacked on to the actual number of days the foreigner plans to stay in Ukraine, for good measure.
In other words, the formula is 784N + 3920, where "N" is the number of days you plan on being in Ukraine*.
So, here are the amounts you'll need to prove you have at your disposal for stays of different lengths:
1 day: 4704 UAH (approx. $400 USD)
7 days: 9408 UAH (approx. $800 USD)
30 days: 27440 UAH (approx. $2500 USD)
90 days: 74480 (approx. $6500 USD)
* However, it is unclear whether the extra 3920 UAH will need to be included for stays of one month or longer.
Exemptions from this requirement are: diplomats, employees of international organizations on official business, and foreigners with Ukrainian residency.
Acceptable documents proving financial solvency include: bank statements, ATM receipts, credit card limits, cash, or a letter of support from an inviting party. These documents do not have to be certified. If no documents are provided, foreigners may be refused entry to Ukraine.
Also, to demonstrate your declared length of visit, you may need travel/transit documents (return/out-bound tickets).