Q. (Re- Above question on a kinyan (acquisitive act) for the matzos eaten at the seder by family and guests). Is it advisable that the guest pay a symbolic amount to the host for the matzos to be eaten later at the seder?
A. Some Poskim indeed maintain that it is better if something, at least a perutas value, is paid to the host by married children and guests for the matzos. (Piskei Teshuvos 454: 2).
Another reason given is mentioned in question 1923 in regards to a gifted taalis, were we wrote: "Chaye Adam (68: 16) rules that one should not comply with a mitzva for free, but rather pay for it. As King David said to Aravnah, “No; for I will only buy it from you at a price; so that I will not offer to the Hashem my G-d burnt-offerings which I had received for nothing.” (Shmuel II -24: 24). He quotes the Zohar (Terumah) who is very stringent in this principle, and warns that a spirit of impurity rides with free gifts.
Horav Shlomo Miller's Shlit"a opinion is that the above may be a virtuous middas chassidus, but it is not customary
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit'a