The “vintage telephone effect” on vocals has been in vogue, in particular in lo-fi and electronic music, since Beck’s debut album came out in 1994. Although the market is saturated with “lo-fi” plug ins, all you need to recreate this trick is some EQ, compression and distortion. Compress the vocal track heavily – you can even try with a limiter if you wish – then use a high pass filter on the bass frequencies sweeping from the bottom end to the mids, until you get the sound you are looking for. Then cut also a little bit of the high frequencies with a low pass filter, and make the voice even more nasal with an mid eq boost in the 2-4kHz range. Add a little bit of distortion and… voila’.
Another way to get a similar sound is to do what Julian Casablancas did when recording the vocals for “Is This It”, i.e. feed the line output of you mic preamp to your cheap guitar amp (he used a Peavey practice amp).
Tweaking will be necessary to get the right tone of course, and if it sounds weird you may want to try using a re-amp box between the preamp and the amp.