No you can't. You need to own some monero on your own first.
Why, for paying the security deposit.
The goal here is to discourage scammer. So if a scammer is trying to scam you $100 and he fail, he will lose $120.

That is why scammers are very rare on Haveno or Bisq.

If you have no monero right now, but you have btc, you can trade some of your btc for monero with Bisq.

If you have only cash. maybe you should buy some kyc bitcoin first then trade them for monero on bisq