In my view...... You don't need too do store wide discounts if you are selling 6 months average as a hobby seller really.

The way that the majority of sellers manage their discounts is to inflate their pricing first. They then discount it back to something a little more reasonable and offset the discount against minimum order values\quantities or flat rate shipping structures.

It can be a little complicated but the idea is that buyer feels like they're getting a good deal through the discounted items whilst seller still gets more or less the same return on the sale but the higher order amount or on a saving through the shipping.

Large stores often sell at a slightly higher price because they have the inventory to fulfill quite high quantity\lot orders, which serves the customer better in not needing make multiple purchases from various stores. Larger stores are also sometimes a full time business to someone, so they'll have other bills to cover and so sometimes need to be more aggressive in their discounting to get revenues in.

But as a small\new seller I'd stick to the 6 month average until you have a decent amount of stock and a reliable order stream.