The FDIC Trust Examination Manual used to be available without charge on the FDIC's website. I see now that they have disabled that link (BTW the S&S and Comp Manuals are still available - Is that disparate treatment?)
None the less, the $100 cost for the manual is not out of line, but before I would spend the bucks, I would inquire as to whether it is current on with legislation passed in the past couple of years (specifically GLB, USA Patriot Act, and Sarbanes-Oxley) If it is then I think it would be money well spent. If not, you may want to consider taking a look at both the OCC Asset Management Handbook Series and the OTS Trust Examination Manual. The FDIC may be your primary regulator, but I have found that the basics are the same and unless the FDIC is willing to provide theirs to you without charge, I think the other two may get you over the hurdle.
Finally - not to bash the FDIC at all - that's not my intent, but IMO the OCC is the trust industry's premier regulator. The OCC routinely sends large numbers of their examination staff to industry sponsored training in addition to in-house sponsored training. The FDIC might send one or two of their staff to an annual industry sponsored conference, but the bulk of the FDIC training is done in-house and having talked with a couple FDIC Trust examiners, is not all that "cutting-edge". The OCC is also by far and away the primary regulator for more trust assets under management than the FDIC, so if you subscribe to the notion that bigger is better and it is the industry that formulates and innovates and not the regulators, then maybe the OCC Asset Management Handbook series is worth looking at - and best yet - its FREE!