An author's update:
Book 1 in The Parallel Universe Adventures series, Whole New World[s], published a week ago; selling slowly, probably only to people I know (all UK sales so far, no others). 1 review (5 star, natch).
Book 2, Running, nearly finished first draft - just two or three chapters left; the end is in sight! Book cover already ordered from my designer. Going to look good!
Spend so far: Too much! (Mostly in website, ISBNs, covers, and a bit of advertising which has so far failed to get results.)
Conclusion: Learnt so much, still lots to learn. Having fun with the writing bit, not so much with the marketing. Frustrating, slow and not very productive as yet. Onwards and upwards!