At first blush, the answer to the question posed in the title of this post would seem to be yes. Unfortunately, the answer is actually “no.”
As I’ve written about before, charitable contributions must be substantiated. If you give less than $250 at any one time, you can substantiate the donation in any reasonable method, such as showing a canceled check. You don’t necessarily need a receipt from the organization.
So let’s say you toss $20 into the collection plate at your church each Sunday. Each of those donations individually is less than $20, so the relaxed substantiation rules apply.
HOWEVER … if you’re audited, you still have to be able to prove the donation. You don’t need a receipt from the church because each individual gift is less than $250, but you still need a paper trail to document the donation.
As the “PPC 1040 Desk Reference Guide” says:
Charitable cash handouts—such as cash placed on church collection plates—will not result in any deductions unless the donor obtains a qualifying receipt or written communication.
(From Key Issue 26C: Substantiating Contributions, PPC’s 1040 Deskbook)
So unless you can get the church to give you a receipt for the cash you toss into the collection plate, you’re out of luck in taking the deduction.