Has this been said already? Dog training. Our 1 year old dog is a pleasure to be around, both in public and at home, because she's so well-behaved. This was an investment of time more than money, but we used an online training program and then found an awesome local trainer who does small group classes, and both the time and the money have been well spent. The classes have also been fun for the humans, since they kind of turn into a little social event each week. When my husband said he wanted a particular breed that's large and powerful, I was afraid that we could end up with a scary, out-of-control dog, but she's an absolute lovebug who gets pets and compliments everywhere we go. She usually wears a pink or purple collar to make her look a little less intense. :-)