Machine/welding shops don't want to mess with itty bitty one off jobs, unless the customer is willing to pay. It was common for us to over quote/bid just in case of the job being a real bitch (You know, Murphy. Shit happens). Snap a tap off in a hole and your $100 job, including profit, just ended up costing the shop $200. Drills and taps are much harder to remove than any stud.
However, drilling and tapping is not hard. You just need to be careful. Make sure the tap is in line with the hole. That may seem like a real Duh, but most of the taps I have seen that have broken are because the tap got into a bind due to misalignment. They're hard, but quite brittle.
When you are tapping and the tap is advancing you need to stop and back out the tap 360 degrees to break the chip. Do this about every 2-3 turns and back out completely to clean the flutes of the tap of any chips. Keep doing this until you reach the bottom. It may seem to be more time consuming, but it's necessary if you want to prevent tap breakage.
Also, no cutting fluid is necessary for cast iron. An air hose is nice, but cast iron chips are nasty black. Picture grinding up pencil lead and then blowing it all over the place.
For Aluminum you really need fluid for Aluminum. Alumicut comes to mind.
Steel, general cutting fluid. Motor oil will work, but it's not ideal and can be rather funky if using a power drill or press. But, then again, most cutting fluids are pretty nasty. The place with "The wealthy Hardware Man" will have it.
Sorry about rambling on. I was a machinist/welder in my previous life and figured a few tips might be helpful.