While 'good' is quite relative, in the audiophile parlance it will be difficult to get 'good' tower speakers within 30K. Your best option is to look at the used market and you can get some really great value for money at times. Either that or you will have to increase your budget by quite a bit for new speakers.
Plus unless getting towers is an absolute must, you should generally consider bookshelves in the same budget. Almost always the better performing option in tight budgets.