Cap Collector

Cap Collector is a perk in Fallout 4.

Characteristics
This perk enhances workshop settlements with better bartering power. Alongside the equivalent ranks of the Local Leader perk, it allows one to craft trading stands in settlements, such as the trading, armor, weapon, and clothing emporiums. It is also required for the surgery center and restaurant.

Rank 1 and 2
Stack multiplicatively, giving a total bonus of 32% (1.2 * 1.1) for selling and discount of 28% (1 * 0.9 * 0.8) for buying items.

Rank 2 allows (with Local Leader 2) the creation of the emporiums, the highest tier of store that can be constructed, and which is required in order to assign the expert or 'tier 4' traders such as Smiling Larry, Trader Rylee, etc.

Rank 3
The option to invest in shops is now available, accessible via the bottom of the shop screen in one's Pip-Boy.

For settlement shops, investing 500 bonus caps into their inventory applies to all instances and all tiers of that particular settlement shop type (weapon, clothing, general, etc.) across all allied settlements. However, bear in mind that these caps are shared, so there are only 500 caps to be obtained from each settlement shop type, though one is free to choose the most convenient location with which to trade.

The player character is not limited to their own settlement merchants, but can also invest in almost all of the merchants.