For RSX format documents the following pricetypes are available

AAA = NETPRICE
net is inc tax Final price, includes any discounts/allowances, fees/charges, or taxes. This is a UNIT price (per each, carton, case etc.)

AAB = GROSSPRICE
gross is ex tax Final price, not including any discounts/allowances, fees/charges, or taxes (QTY x Base Price). This is a UNIT price

AAE = GROSSPRICEINCTAX
grosspriceinctax is inc tax Final price, not including any discounts/allowances, or fees/charges. It is AAB + TPU. This is a UNIT price

UCP = UNITCOSTPRICE
raw cost ex tax/charges Price retailer pays vendor for goods. This is a UNIT price

TIP = TOTALLINEITEMPRICE
Qty * Price including any discounts/allowances, fees/charges, not taxes. This is a LINE price (15 x 1 case etc.)

NWT = NETPRICEWITHOUTTAX
Unit price including discounts/allowances, fees/charges but excluding taxes. This is a UNIT price. Effectively AAA minus tax.

TWT = TOTALLINEITEMPRICEWITHTAX
Qty*Price including discounts/allowances, fees/charges, and taxes. This is a LINE price

TPU = Tax per unit
The amount of tax applied per unit  not including any discounts/allowances, fees/charges

Also note that 

PurchasePrice is the unit price based on the PurchasePriceType where AAA = Price in tax, AAB - price ex tax, and UCP = is based on whether the retailer is sending inc or ex tax prices