A lot of times the spigots that come with those cheap jars (I bought mine at Marshall's too) are not really food safe or have metals in them that can react to the acidic kombucha and leech into your brew... just to play it safe I buy stainless steel spigots on Amazon, like this one: https://www.amazon.com/dp/B013FWX4HA/ref=cm_sw_r_cp_api_Adk3yb90A9RBW
I feel ya there!! I'm currently in the process of switching to a wider mouth 1.5 gallon jar that came with plastic spigot (just waiting on a 304 stainless steel spigot from Amazon before I switch over) and over the past 1.5 years I've been using 3 0.5gal Ball jars which have relatively narrow openings compared to the main diameter of the jar, making it annoying to get the pellicles out.
I just recently added a stainless steel spigot to my Alexapure Pro (much like big Berkey). They come with silicone seals, and feel incredibly solid.
I bought two of these from Amazon. Beverage Dispenser Replacement Spigot,Oak Leaf Stainless Steel Spigot Polished Finished, Dispenser Replacement Faucet https://www.amazon.com/dp/B013FWX4HA/ref=cm_sw_r_other_apa_i_2TIOEb161DH8J
get an all stainless spigot - this is the one i use:
https://www.amazon.com/gp/product/B013FWX4HA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1