Walmart offers the Stalwart Diversion Book Safe for $9.99. Opt for in-store pickup to dodge the $5.99 shipping fee. That's the lowest price we could find by $2, although we saw it for around a buck less in our mention from last September. It looks like a copy of The New English Dictionary, but it's actually a lockbox with a hidden storage area. Two keys are included.
Uncle Sam could take a hefty chunk of your retirement income if you botch this.