Metal porch railing isn't cheap, I found a way to make railing from cheaper metal fencing at about 1/2 the cost. All you need is a 3D printer and a free program like 123D to make the mounts.
Step 1: Make Your Mounts
With 123D dropping a few squares and circles makes it easy to design the mount you want.
If this is your first time using 123D don't get excited, Play around add some shapes and delete them. In no time you will get the hang of adding shapes to make other shapes.
Remember to add a few mm to your measurement as the plastic will shrink a bit.
Step 3: The Print
After you design your mounts, It's time to print. You can print in any color and use them or spray paint them.
This will be the hardest part. You need to figure out how heavy a part you want/ After you print one I would test fit and mount it to make sure it's strong enough.
Step 4: Install
So after you print and paint (if you need to) install the fence. It's that easy. I made mine to be mounted with 2 deck screws. The STL is on Thingiverse and free to download, it will work with the lowes no dig fence.
Good luck, Have fun.