I have recently done many software upgrades and a new color printer. I was at the point where my old printer had lived a long useful life (7 years!), and then died, but it's OK. My new printer uses microprint technology to use less ink, but also delivers better prints, and borderless ones as well. So I'll see a return on that investment fairly quickly, as I'll be able to use it for client projects and also be able to print out materials for small self-promotions, so that works out well.
And the software upgrades were long over due. When you're a solo designer, upgrading software frequently may not be an option financially, but there comes a time when one can't hold out any longer. My latest upgrades will allow me to produce certain kinds of work faster, and share documents better with colleagues who help me produce my work. So, while there's not a direct "marketing" benefit to my purchases, I'll save time and money.
I have also "purchased" good services this past year. I can't say enough about a good Virtual Assistant. (Thanks Brianna!) Viva la outsourcing! Seriously, there are not enough hours in a day, and good help can make your business more profitable if the work outsourced is done well and frees you up to work on other things you can bill for or for time you can spend new business development.

