Every shul sells aliyos and kibbudim, and on Simchas Torah it becomes a full auction where the biggest bidder gets the mitzvah. I want to understand what is going on halachically.

1. Where does the aliyah itself come from? Krias haTorah is derabanan from Moshe and Ezra, so what exactly is the mitzvah a person gets when he is called up, and why do people treat certain aliyos as such a big deal?

2. What is the source for selling mitzvos at all? The poskim record the minhag of selling aliyos and mi sheberachs, even on Shabbos where buying and selling is normally assur derabanan. How did selling a mitzvah become allowed, and what is the logic behind it?

3. When the auction turns into a status game, the same wealthy people win every kibbud and it becomes about honor, is that still a kiyum of chashivus haTorah or is it the opposite, turning the Torah into a kavod contest? Some communities banned selling aliyos for exactly this reason. Which side is right?

4. Practically, if a shul wants to honor the Torah without turning it into an auction for the wealthy, what is the right way to do it?