My wife and I have lots of toys and are always a good thing to have in the nightstand. But first talk to your girl to see what kind of stuff she want... She maybe just want a little finger vibrator and you bring home an horse dildo can get you in trouble
For me the best first things (cheap and effective) are a vibrating cock ring, bullet vibrators, lube and maybe a butt plug. Simple lingerie as thongs and stocking are also good things to spice up.
For a next step, improve the lingerie with corsets, garter belt and bras for her, some see though or funny undies for you. Cosplay is also an option. For couple toys, an air pulse toy like the satisfyer or womanizer mean orgasms in 2 minutes or less (my wife can confirm that with her satisfyer), and a couple vibrator like the Partner Whale.
If both want to go further in kink, restrainers, blindfolds, spanking paddle are also great options. And if you like butt stuff, a pegging dildo or prostate plugs are great.