Hi! I know this thread might be dead but I thought I would give some input as well since it might help someone. You see, when working with type it all boils down to licensing of the font-files rather than the typeface itself. A typeface in itself cannot be copyrighted and in theory if you were to trace a typeface by hand and make your own font file out of it you could use this font as much as you like without paying royalties, even without alterations. A lot of typefaces have done this and are largely based on older typefaces two famous examples of this is Arial which is modified version of Helvitica and Helvitica itself which is based on some 1800s Grotesk typeface which’s name eludes me. Wiki it for a good read some day.
This means that there are actually a rather large amount of typefaces floating around that are identical to Helvitica but are named differently since the name is trademarked. What I would do on a zero budget is to look around on opensource font sites and find a good Helvetica clone and simply use it. A lot of them have pretty good kerning and ligature. Check out: http://www.google.com/fonts , https://www.theleagueofmoveabletype.com or sites like http://www.fontsquirrel.com/ .
Also, Helvetica isn’t that great, to me it feels so corporate and Orwellian that I can hardly stand to look at it and when designers constantly resorts to standardized defaults it just looks so dead. http://endtimeheadlines.files.wordpress.com/2013/05/they-live-billboards-messages-john-carpenter.jpg