Apparently, while Biden did sign a Lend-Lease act specifically for Ukraine (which is like a long-term loan that needs to be repaid), he instead mainly used other US programs to supply economic and military aid to Ukraine:

Ukrainians have often asked why Lend-Lease isn’t operational. Washington has clarified that Ukraine receives military assistance through three other American budget programs: Ukraine Security Assistance Initiative (USAI), Foreign Military Financing (FMF), and Replenishment of US weapons stocks (PDA). Unlike Lend-Lease, which involves leasing or lending weapons, these programs provide free assistance to Ukraine, making them even more advantageous for Kyiv. - EuroMaidan press, Lend-Lease for Ukraine: Is it dead or just on hold?

So Biden chose not to use the lend-lease act, and instead used the USAI, FMF and PDA programs to assist the Ukranians. While this is claimed to be "free" by both US and Ukranian politicians, Ukrainian Ambassador Valeriy Chaly once remarked to BBC:

I have a question – why does everyone assume we will have to pay [for the weapons]? The point is that all of this should be spelled out in an agreement. Whether to pay or not pay, or simply have a condition to return undamaged equipment [after the war], we do not know, because there is not even a draft of such an agreement yet,” the diplomat remarked.

Was any such agreement made between the US and Ukraine? And how much of Ukranian aid from the US is unconditionally free, with conditions or a loan?

(Note: Conditions could also include separate government agreements similar to IMF or World Bank like terms that disburses loan only if the demands for structural or economic policy changes are made by the borrower country.)