Price resolution

PriceEngine::price_for_user() resolves the price a customer sees in a fixed order. The first step that applies wins.

1. Manager switcher override — when a manager is previewing as a tier/customer.
2. Per-customer price set on the product — a negotiated price beats everything.
3. call_for_price rule — force the price empty ("Call for Price").
4. Hide-Pricing visibility role the customer matches → empty price, unless the product force-shows the price to this customer.
5. Category → role mapping (optional, per user).
6. skip_matrix rule — leave the incoming price untouched (everyone sees MSRP).
7. Tier resolution among the tiers the customer holds: always override › when_priced override › lowest remaining tier price.

Within a single tier

price_as_tier() computes one tier's price:

1. MSRP (regular price) as the starting point.
2. The tier's explicit price for the product, if set.
3. no_tier_discount collapses a discount tier to its plain base price.
4. Multiplier fallback — multiplier × base role's price when no explicit price.
5. Chained fallback_to — MSRP or another tier.

Zero prices

The effective price a customer sees (effective_price(), the lowest of the resolved regular and sale prices) treats an exact 0 as "not yet priced" and blanks it to an empty price ("Call for Price"). This matches stores where 0 is a placeholder rather than a genuine free price.

A store that sells real $0 products can keep the zero by returning true from the wc_pricebook_allow_zero_price filter — globally or per product/user:

add_filter( 'wc_pricebook_allow_zero_price', '__return_true' );

Visibility vs. price

"Hidden" comes in two flavors, and they're independent of the number above:

• Hide Product removes the product from the catalog entirely.
• Hide Pricing keeps the product visible but empties the price ("Call for Price").

Both are driven by visibility roles and can be overridden per product by force overrides.