We have a Bichon x, he was from a rescue, we got him 4 years ago. The rescue asked for a donation, I think it was £100. We had to buy his bed, water and food bowls, food, lead, collar, toys, a car harness and a coat for him - he hates getting wet:) just to mention the initial outlay needed. He was on Hills Science Plan food as that was what the rescue centre fed him on, so we continued with this for a while until it started going up dramatically, we changed to James Well Beloved, which he likes, but now alternate his meals with dried and wet food. We have never bothered with insurance for him, he was covered for a little while when we first got him, through the rescue centre, but when that ran out, we didn't renew. We are fortunate enough not to have to worry about unexpected bills. He has had a couple of large vet bills at £400 + and £200+, plus one other of £200 + when he was attacked by another dog, but fortunately the other owner paid that bill. Apart from these, I think the biggest costs were grooming, he was needing to be done every 6 weeks at £35 a time, but my daughter is now a trained dog groomer so he gets done when needed at no cost. The worming tablets from the vets only cost £4, I get a prescription for his flea treatment and buy online from Petmeds. He gets an annual booster for his vaccination and gets a health check at the same time - this costs about £40.
We would not be happy putting him in kennels, so for the last few years have holidayed in this country in places where we could take him, which is great however most holiday places that accept dogs will not allow them to be left in the property unattended, so this can limit what you do on your holiday.
To sum up though every day our dog does something to make us smile or laugh, we certainly wouldn't regret getting him and is worth every penny we have or ever will spend on him.