My inspector (who really does know everything!) owned, renovated & managed over 60 properties, was a GC, became an inspector & is certified/licensed in 3 states.
I don't think three days' instruction is going to give you much more than an overview of the process & a general idea of what to look for. That's not a bad thing - if you're starting out, any information is better than none. But it will take many years & many, many properties to become truly knowledgeable.
Personally, I'd keep the money, read everything I could get my hands on & ask a local inspector if you could tag along. They may say no, but it doesn't hurt to ask! Go look at homes for sale & ask the realtor questions like crazy. (The realtor I use used to be a contractor/investor, so he knows his stuff. Many don't, but it's worth a shot.) If there's a rehab going on, knock on the door & ask if they have time to give you a tour. Lots of folks are very pleased to share what they know.
I've learned more from asking questions of the various professionals around town than you could imagine. I'm sure the plumber doesn't appreciate me crawling under the house with him & pestering him like a seven-year-old, but it's my money & I'm getting every penny's worth!