Last year I did a course "Electronic Measurement" at USQ which dealt a lot with EMC compatability, PCB layout, noise resistance, etc - a lot of really non-obvious stuff until you read it.
From this I've ended up with bundle of very enlightning PDFs, some of which I'll list below. I'm not sure if these are what you are looking for, but they certainly match your price range. I recommend anyone every using an op-amp read at least the first one, which I found quite amazing - for illustrating the different return paths AC and DC take across a PCB. In general, search the application notes of the device maufacturers - particular Analog Devices.
+ AN-345 Grounding for Low-and-High-Frequency Circuits.pdf
+ EMI and Layout Fundamentals for Switched-Mode Circuits R.W. Erickson.pdf
+ AN202 An IC Amplifier Userâ(TM)s Guide to Decoupling, Grounding, and Making Things Go Right for a Change.pdf
+ A Designer's Guide to Instrumentation Amplifiers 3rd Edition (Kitchin & Counts, Analog Devices 2006).pdf
+ Reducing RFI Rectification Errors in In-Amp Circuits (Analog Devices AN-671).pdf
+ Op Amps For Everyone - Design Reference (Ron Mancini, Texas Instruments 2002).pdf
+ Analog Dialogue vol39n3.pdf
+ The Instrumentation Amplifier Handbook (Neil Albaugh, Burr Brown Corporation).pdf
+ Shielding and Guarding (Alan Rich, The Best of Analog Dialogue 1983).pdf
+ Errors and Error Budget Analysis in Instrumentation Amplifier Applications (Analog Devices AN-539).pdf
+ PCB Design Tutorial RevA (David L. Jones, 2004).pdf
If you can't find them yourself, I could upload them (if someone could provide a simple service to deposit them at.)