I use Beteasy. They have all sorts of promos, mainly on sport & aus racing. For your sort of turnover, it will suit. They usually put up the tab fixed odds on nz racing, but odds dont tumble quickly like tabs odds, so gives you more time to get on.
They usually pick out couple meeting first races, that if you place fixed odd bet up to $25, if it doesnt win, they give you a free $25 bonusbet, which when you place it, beteasy will take the $25 back if your bet wins, eg- $25 bonus bet on $4-00 winner, you would get back $75-00.
Also have 2 main aus meetings each sat, put on fixed odds win bet, if it comes 2nd or 3rd, get bonus bet up to $50. I always have a go, quite good knowing you have plenty free bets up your sleeve.
Pay by credit card, deposit back into bank acc, takes couple of days, never had problem