Pricing your item is required when posting goods for sale. A good asking price will ensure a fast sale, but pricing too high may mean your item sits for longer or worse never sells.
Most experienced sellers price their items 10-15% under the average selling price for items of the same brand, make, and condition on eBay.
Items with complete packaging, manuals, and all accessories will sell for more than items missing these items.
Different brands and models can sell for more or less depending on favorability. Selling an item new 2nd hand may void a warranty, and can affect pricing as well.
Pricing an item as $1234, or $1 OBO is not allowed either. Ensure that your asking price is a realistic number.
Asking a high price for a rare, or hard-to-find item is allowed within reason. Asking $10,000 for a brand that no longer makes an item, when other brands still sell it for $100 is not allowed.
Price gouging, or scalping is not inherently against the rules. Just ensure that you are respecting other sellers and buyers when doing so. Buying in excess on HardwareSwap to resell on another platform, or even reselling on HardwareSwap is not directly against the rules, but doing so may consider you a reseller, which must follow reseller rules.