If you're on a tight budget, I'd focus on those areas where you'll mostly be walking on bare tile in bare feet (ie bathrooms). Electric radiant floor heating in a small bathroom won't cost too much to install or run. If you try to run it off your hot water heating system, the installation cost will be quite a bit higher.

Electric radiant floor heating is a luxury item. It is expensive to install and operate. If you are on a tight budget then it is not the best option in my opinion.

Why are you considering this? Is this a new house and are you worried you will not be comfortable in the winter?

I'm worried that the floor will be TOO cold in the winter (very harsh winters here). It seems like many people here get it installed these days. If we're installing a more permanent flooring like tile, I'd rather pay upfront to have it vs. regret not getting it later.. but at the same time we already have what I've heard are efficient heaters at the ground level. This will be our first winter in the home (we bought it in June).

I have it in my bathroom and love it, but my entire house is heated by in-floor hydronic radiant heat. You ask if you "need" it. Assuming this is not a brand new house, probably not. Since you haven't had a winter there, I would wait. I think you can get plug-in electric radiant pads which you could try out this winter.