In In-App Billing v3 library I have this method "GetInventoryInformation" an I can get the information the price using this code:
B4X:
Sub billman3_InventoryCompleted (Success As Boolean, Products As List)
If Success Then
For Each sk As SkuDetails In Products
Dim parser As JSONParser
Dim s As String = sk.toString
Dim i As Int = s.IndexOf(":")
s = s.Substring(i + 1)
parser.Initialize(s)
Dim root As Map = parser.NextObject
price = root.Get("price")
Next
End If
End Sub
You should call QuerySkuDetails and wait for the SKUQueryCompleted event. It will include a list with the SkuDetails objects. The price should be there.
Wait For (sf) Billing_SkuQueryCompleted (Result As BillingResult, SkuDetails As List)
If Result.IsSuccess And SkuDetails.Size = 1 Then
Dim sku As SkuDetails = SkuDetails.Get(0)
log(sku.getPrice)