diff --git a/job_submit_fx/billing_cost_estimate.lua b/job_submit_fx/billing_cost_estimate.lua
index c2ee866..1c39c31 100644
--- a/job_submit_fx/billing_cost_estimate.lua
+++ b/job_submit_fx/billing_cost_estimate.lua
@@ -1,134 +1,148 @@
 -- Function billing_cost_estimate to display job cost --
 function billing_cost_estimate (job_desc, cpu_cost, gpu_cost, corespernode, gpuspernode, defaultwtime, defaultpartition, parallel, serial, submit_uid)
 
   -- Initializing local variables
   require('job_submit_fx/scitas_debug.lua')
   local gputres       = nil
   local gpu           = nil
   local chf           = nil
   local timeinsec     = nil
   local nodetres      = job_desc.min_nodes
   local cputres       = job_desc.min_cpus
   local wtime         = job_desc.time_limit
   local partition     = job_desc.partition
   local ntaskpernode  = job_desc.ntasks_per_node
   local costunit      = "cpu"
   local debugmode     = scitas_debug(job_desc)
   local infisixteen   = 65534
   local infithirtytwo = 4294967294
   local arrayindex    = 1
+  local freeparts     = {'build', 'debug'}
+  local isfree        = 0
 
 
   if partition == nil then
     partition = defaultpartition
   end
 
+  -- Free partitions
+  for i, fpname in ipairs(freeparts) do
+    if partition == fpname then
+      isfree = 1
+    end
+  end
+
+
   if job_desc.array_inx ~= nil then
     ak, av = string.match(job_desc.array_inx, "(.*)%-(.*)")
     if tonumber(ak) ~= nil and tonumber(av) ~= nil then
       arrayindex = tonumber(av) - tonumber(ak) + 1
     end
   end
 
   if job_desc.gres ~= nil then
     gputres       =  string.match(job_desc.gres, "gpu.[0-9]+")
   end
 
 
   -- Convert time in seconds
   if wtime == nil or wtime == infithirtytwo or wtime == infisixteen then
     timeinsec = defaultwtime
   else
     timeinsec = wtime * 60
   end
 
 
   -- Update cost unit if user request GPUs
   if gputres ~= nil then
     gk, gv = string.match(gputres, "(.*)%:(.*)")
     gpu=tonumber(gv)
     if gpu == nil or gpu < 1 then
       costunit = nil
     else
       costunit = "gpu"
     end
   end
 
 
   --
   -- User does not define the number of nodes
   --
 
   if nodetres == infithirtytwo or nodetres == infisixteen or nodetres == nil
   then
     if string.match(partition, serial) then
       node = 1
     else
       node = 0
     end
   else
     node = nodetres
   end
 
 
   -- CPUs
   -- First case: user does not define the number of CPUs
   --
   if cputres == infithirtytwo or cputres == infisixteen or cputres == nil then
     cpu  = corespernode
   --
   -- Second case: user defines the number of CPUs
   --
   else
     cpu  = cputres
   end
 
 
   --
   -- Special cases
   --
   if string.match(partition, parallel) then
     cpu = corespernode
     if tonumber(cputres) >= tonumber(corespernode) and node == 0 then
       if ntaskpernode == infithirtytwo or ntaskpernode == nil or ntaskpernode == infisixteen then
         node = math.ceil(tonumber(cputres)/tonumber(corespernode))
       else
         node = math.ceil(tonumber(cputres)/tonumber(ntaskpernode))
       end
     end
   end
 
   --
   -- Calculating price
   --
-  if costunit == "cpu" then
-    if cpu == infithirtytwo or node == infithirtytwo then
-      slurm.log_info("billing::: cannot determine the values to calculate the price")
+  if isfree == 1 then
+    chf = 0
+  else  
+    if costunit == "cpu" then
+      if cpu == infithirtytwo or node == infithirtytwo then
+        slurm.log_info("billing::: cannot determine the values to calculate the price")
+      else
+        chf = cpu * node * cpu_cost * timeinsec * arrayindex
+      end
+    elseif costunit == "gpu" then
+      if node == 0 then
+	      node = math.ceil(tonumber(gpu)/tonumber(gpuspernode))
+	    end
+      chf = gpu * node * gpu_cost * timeinsec * arrayindex
     else
-      chf = cpu * node * cpu_cost * timeinsec * arrayindex
+      slurm.log_info("billing::: cannot determine the unit type")
     end
-  elseif costunit == "gpu" then
-    if node == 0 then
-	    node = math.ceil(tonumber(gpu)/tonumber(gpuspernode))
-	  end
-    chf = gpu * node * gpu_cost * timeinsec * arrayindex
-  else
-    slurm.log_info("billing::: cannot determine the unit type")
   end
 
   --
   -- Print the price --
   --
   if chf ~= nil then
     if debugmode == 1 then
       slurm.log_user("billing::: cpu: "..cpu)
       slurm.log_user("billing::: gpu: "..gpu)
       slurm.log_user("billing::: node: "..node)
       slurm.log_user("billing::: timeinsec: "..timeinsec)
     end
     slurm.log_user("The estimated cost of this job is CHF "..string.format("%.2f",chf))
     slurm.log_info("billing::: cost "..submit_uid.."|"..chf)
   else
     slurm.log_info("billing::: cannot calculate the price")
   end
 end