The main part of the mitzvah of Pidyon HaBen is redeeming the bchor yisroel using five silver coins. But, is it that simple? are there other options for redemption? may the אבי הבן make conditions that the silver coins be returned? may he use cash, check, paypal?
Kehuna.org, the official website of איגוד הכהנים, wishes that the Pidyon HaBen should be done לכתחילה -initially- the best way possible. We advocate that the coins be given to the kohen for keeps and without condition of any kind, lest the Pidyon be in fact invalid.
With that said, let us explain why we advocate the complete and unconditional giving of the five silver coins to the kohen;
The talmud (מסכת קידושין דף ו עמוד ב), quotes Rava as saying that if one gives money to the kohen saying here it is on condition that you return it, the son isn’t redeemed. This type of condition is titled מתנה על מנת להחזיר -a “giving” on condition that it be returned. Generally speaking, such a gift is considered a legitimate transaction (Talmud sukkuh, 41b, Pirush HaMishna of the Rambam, Sukkah 3:11). But, regarding the mitzvah of Pidyon HaBen, such a transaction is forbidden for another reason; as it makes the kohen look as if he is being מסייע בבית הגרנות -helping thresh wheat so that the field-owner should grant him his kohanic gifts (and not another kohen) Sefer Ha’Agudah p. 213.
In addition, one of the biggest concerns with giving the coins on condition that it be returned is that the kohen feels compelled and pressed to agree, either because he is “put on the spot” five minutes before the transaction or for not wanting to “be too hard” on the אבי הבן at his time of simcha or for any other reason. The kohen may be told that the five silver coins are a rare “collectors item” are “special ordered from Israel” or are needed for framing on the baby’s Pidyon HaBen certificate.
The kohen may even say “no problem” and agree to return the coins in exchange for cash but we are concerned that he agreed only because he was put on the spot and thus his agreement is half-hearted.
The Chasam Sofer lables such a pidyon is invalid (Shu”t Chasam Sofer to Yoreh Deah, responsa 291), and we agree.
Using cash or check
As to the validity of using payment types other than five silver coins for the Pidyon transaction, The Mechilta (שמות 13:13) and Sifri (במדבר 18:17) have this discussion; The two psukim, “וכל בכור אדם מבניך תפדה” “every human bchor from your sons you should redeem” and “ופדויו מבן חדש תפדה(במ’ יח טז )” “and his redemption is from one month, you should redeem”, are both a כלל -a general instruction without detailing how to actually go about the redeeming process.
A third possuk, however, gives a פרט -actual detail- how to go about doing the redemption; “בערכך כסף חמשת שקלים” “in your valuation, silver, five shekels”. The medrash goes on to label this a כלל ופרט וכלל, where the rule is that we derive our ruling from the פרט -the detail- that fixes the transaction to five silver coins which are “tangible, not is use as a security interest, and its makeup is money” so too, the item used for the pidyon transaction is required to have these attributes, whereas human servants, monetary notes, real estate and הקדשות -sanctified property- don’t have these attributes, and may not be used for Pidyon HaBen.
The talmud (מסכת כתובות דף קב עמוד ב) mentions that if the אבי הבן writes an “I owe you” note to the kohen for the value of the five silver coins, the bchor is not redeemed. This is a rabbinic enactment to pre-empt people from thinking it is okay to redeem using documents (i.e. cash).
It is best to use five silver coins for the pidyon and to give them to the kohen entirely without condition. It is also best to avoid using an alternate form of payment other then five actual silver coins when doing your pidyon.