Tenant question, Washington DC - 1st/last before lease and seeing unit?

Hi all,

I'm looking to rent in DC for the first time. I'm going off of Craigslist right now, and with 3-4 potential contacts/landlords on the other end of the email exchange, I've hit something along these lines:

"This apartment is generating a lot of interest, so if you want it taken off the market and reserved for you, give us 1st month's rent and your deposit. Then you can tour the unit, sign the lease, etc. If for whatever reason you don't like the unit, this money will be fully refunded to you."

Is this typical, or is this a scam? It's worth noting that my typical Craigslist scammer 6th sense isn't going off for these people, and the fact that more than one of them has suggested this leads me to believe either a) this is how it's done, b) this is how it's done in a pandemic, or c) it's how SCAMMING is done on Craigslist.

And if this is typical and how it's done, how can I ensure that this money is safely held and that I would get it back? Is there something I can look for in the lease agreement?

Thanks. This is new territory for me.