Can't believe no one's suggested Fuji C200 yet. I think it's an awesome film if you give it good light. Literally the cheapest film available, $3.33 at Adorama for rolls of 36. I rate it at 200 and get tons of keepers, it is more forgiving than Ektar. I find the colors are saturated but not in the same was a Superia 400, which I don't like. You can totally get a portra-ey look from C200. I wish they had it for medium format. Crucially, I think it's also an easy film to scan and color correct.
But that said, Portra 400 is an objectively better film with more latitude and the exact color palate you desire and I would recommend that as a beginner you just get it and swallow the price. You will get more keepers and after the price of processing the cost of the film is a minor factor. If, for every roll of 36 you get 5 keepers when you shoot Colorplus and 10 keepers when you shoot Portra, don't you think the extra $5 is more than worth it when you take into account the $10 you have to spend on developing (probably)?
In my opinion, the only time cheap film ever makes sense nowadays is if you like the look of a particular cheap stock, or if you do all the development yourself and shoot a ton of film.
People who shoot a roll a week or a roll a month and send the film to a lab should not worry about the cost of the film itself. /rant