Do you or your husband have money budgeted that can be spent on whatever? Do you set aside an amount from his, or your paycheck(s)? Or do you just spend what you like, or run all purchases by each other?
I just ordered the Every Day magazine deal that Kim posted. I wasn't actually planning to tell my husband I was spending that $4.50 (not that I was hiding it, but that I didn't feel like I needed to ask permission or anything) then I remembered that I've been saving some money in Paypal. I get $10 or $15/month residual income from some articles I've written, and I save it just to spend on purchases like this. So I spent it from there instead.
We both kind of spend what we like, because neither of us makes very many purchases for ourselves. We don't go out for coffee, or buy ourselves "toys" or anything.