My very talented sister Julia and I have had a long standing pact that when I got married, she would make my wedding cake. This may sound like folly, but she just so happens to thoroughly enjoy making cakes and was no stranger to fondant work. So she made a wonderful chocolate cake with minty frosting between the layers. Just beautiful.
Now topper-wise, Etsy has all kinds of adorable, customizable options, where your likeness can be made into peg figures, or your wedding ensembles painted onto squirrel figurines or (my favorite) a little bust of a tree trunk has your names or initials "scratched" into it. As the wedding got closer, my attention moved away from figuring-out the cake topper to important things like schedules, catering, and booze numbers. (It should have been about what hairstyle I should have, but I will tell you that story later).
A trip to my not-so-local Michaels produced a very simple, pretty and yes, DIY cake topper. And it cost about a buck fifty.
3 wooden pieces, an L, K and a heart, spray painted with blue and red Krylon that we already owned and then each piece was hot glued onto its own wooden coffee stir stick. I was very happy with the results!