>>>I’ll try to remember that principle when negotiating the purchase of a $500 Calabrian esrog or $50/lb box of hand-made shmurah matzoh.
No comparison to rental prices. If you can’t afford it you can easily do without a $500 esrog (or not buy an esrog altogether and just borrow one) or $50/lb box of hand-made shmurah matzoh (or ask for Kimcha D’Pischa. The Gemara says that Arba Kosos etc. in an exception to the rule of
עֲשֵׂה שַׁבַּתְּךָ חוֹל וְאַל
תִּצְטָרֵךְ לַבְּרִיּוֹת)
. When someone is living in an apartment with raising rents they do not always have the easy option to just move