diff --git a/dagger/market.nim b/dagger/market.nim
index 715a008b..7feb11eb 100644
--- a/dagger/market.nim
+++ b/dagger/market.nim
@@ -46,5 +46,5 @@ method subscribeSelection*(market: Market,
                           Future[Subscription] {.base, async.} =
   raiseAssert("not implemented")
 
-method unsubscribe*(subscription: Subscription) {.base, async.} =
+method unsubscribe*(subscription: Subscription) {.base, async, upraises:[].} =
   raiseAssert("not implemented")
diff --git a/dagger/sales.nim b/dagger/sales.nim
index 864da0be..dc3002f0 100644
--- a/dagger/sales.nim
+++ b/dagger/sales.nim
@@ -13,14 +13,16 @@ const DefaultOfferExpiryInterval = (10 * 60).u256
 type
   Sales* = ref object
     market: Market
-    available*: seq[Availability]
     subscription: ?Subscription
+    available*: seq[Availability]
     offerExpiryInterval*: UInt256
+    onSale*: OnSale
   Availability* = object
     id*: array[32, byte]
     size*: uint64
     duration*: uint64
     minPrice*: UInt256
+  OnSale = proc(offer: StorageOffer) {.gcsafe, upraises: [].}
 
 func new*(_: type Sales, market: Market): Sales =
   Sales(market: market, offerExpiryInterval: DefaultOfferExpiryInterval)
@@ -56,10 +58,20 @@ proc createOffer(sales: Sales,
   )
 
 proc handleRequest(sales: Sales, request: StorageRequest) {.async.} =
-  if availability =? sales.findAvailability(request):
-    sales.remove(availability)
-    let offer = sales.createOffer(request, availability)
-    await sales.market.offerStorage(offer)
+  without availability =? sales.findAvailability(request):
+    return
+
+  sales.remove(availability)
+
+  let offer = sales.createOffer(request, availability)
+  await sales.market.offerStorage(offer)
+
+  var subscription: ?Subscription
+  proc onSelect(offerId: array[32, byte]) {.gcsafe, upraises:[].} =
+    if subscription =? subscription:
+      asyncSpawn subscription.unsubscribe()
+    sales.onSale(offer)
+  subscription = some await sales.market.subscribeSelection(request.id, onSelect)
 
 proc start*(sales: Sales) =
   doAssert sales.subscription.isNone, "Sales already started"
diff --git a/tests/dagger/helpers/mockmarket.nim b/tests/dagger/helpers/mockmarket.nim
index a4d1c474..2ad925c9 100644
--- a/tests/dagger/helpers/mockmarket.nim
+++ b/tests/dagger/helpers/mockmarket.nim
@@ -1,5 +1,6 @@
 import std/sequtils
 import std/heapqueue
+import pkg/questionable
 import pkg/dagger/market
 
 export market
@@ -15,6 +16,7 @@ type
   Subscriptions = object
     onRequest: seq[RequestSubscription]
     onOffer: seq[OfferSubscription]
+    onSelect: seq[SelectSubscription]
   RequestSubscription* = ref object of Subscription
     market: MockMarket
     callback: OnRequest
@@ -22,23 +24,39 @@ type
     market: MockMarket
     requestId: array[32, byte]
     callback: OnOffer
+  SelectSubscription* = ref object of Subscription
+    market: MockMarket
+    requestId: array[32, byte]
+    callback: OnSelect
   Expiry = object
     future: Future[void]
     expiry: UInt256
 
 method requestStorage*(market: MockMarket, request: StorageRequest) {.async.} =
   market.requested.add(request)
-  for subscription in market.subscriptions.onRequest:
+  let subscriptions = market.subscriptions.onRequest
+  for subscription in subscriptions:
     subscription.callback(request)
 
 method offerStorage*(market: MockMarket, offer: StorageOffer) {.async.} =
   market.offered.add(offer)
-  for subscription in market.subscriptions.onOffer:
+  let subscriptions = market.subscriptions.onOffer
+  for subscription in subscriptions:
     if subscription.requestId == offer.requestId:
       subscription.callback(offer)
 
+proc findOffer(market: MockMarket, id: array[32, byte]): ?StorageOffer =
+  for offer in market.offered:
+    if offer.id == id:
+      return some offer
+
 method selectOffer*(market: MockMarket, id: array[32, byte]) {.async.} =
   market.selected.add(id)
+  let subscriptions = market.subscriptions.onSelect
+  for subscription in subscriptions:
+    if offer =? market.findOffer(id):
+      if subscription.requestId == offer.requestId:
+        subscription.callback(id)
 
 method subscribeRequests*(market: MockMarket,
                           callback: OnRequest):
@@ -62,12 +80,27 @@ method subscribeOffers*(market: MockMarket,
   market.subscriptions.onOffer.add(subscription)
   return subscription
 
+method subscribeSelection*(market: MockMarket,
+                           requestId: array[32, byte],
+                           callback: OnSelect):
+                          Future[Subscription] {.async.} =
+  let subscription = SelectSubscription(
+    market: market,
+    requestId: requestId,
+    callback: callback
+  )
+  market.subscriptions.onSelect.add(subscription)
+  return subscription
+
 method unsubscribe*(subscription: RequestSubscription) {.async.} =
   subscription.market.subscriptions.onRequest.keepItIf(it != subscription)
 
 method unsubscribe*(subscription: OfferSubscription) {.async.} =
   subscription.market.subscriptions.onOffer.keepItIf(it != subscription)
 
+method unsubscribe*(subscription: SelectSubscription) {.async.} =
+  subscription.market.subscriptions.onSelect.keepItIf(it != subscription)
+
 func `<`(a, b: Expiry): bool =
   a.expiry < b.expiry
 
diff --git a/tests/dagger/testsales.nim b/tests/dagger/testsales.nim
index 1b3e1e09..16967e5d 100644
--- a/tests/dagger/testsales.nim
+++ b/tests/dagger/testsales.nim
@@ -74,3 +74,17 @@ suite "Sales":
     await market.requestStorage(request)
     check market.offered[0].expiry == now + sales.offerExpiryInterval
     sales.stop()
+
+  test "call onSale when offer is selected":
+    let availability = Availability.init(size=100, duration=60, minPrice=42.u256)
+    sales.add(availability)
+    var selectedOffer: StorageOffer
+    sales.onSale = proc(offer: StorageOffer) =
+      selectedOffer = offer
+    sales.start()
+    let request = StorageRequest(duration:60.u256, size:100.u256, maxPrice:42.u256)
+    await market.requestStorage(request)
+    let offer = market.offered[0]
+    await market.selectOffer(offer.id)
+    check selectedOffer == offer
+    sales.stop()