It depends on what your SAAS is and who your target market is. 99% off coupons would work well for the general public but for companies or businesses $5 isn't a lot of money... In fact it isn't a lot of money for the general public either.
Without knowing what your product is it would really be hard to hazard a guess to the best way to market your product or whether subscription is really your best revenue model.
There is merit for you to give them a 99% discount. With virtually every product I've seen offered they have a lot barrier to exit... in fact, they all advertise that its hassle free to exit. The whole point of offering a really low initial price up front is to decrease the barrier to entry, but if you have a higher barrier to exit (or fail to promote an easy to exit method) your acceptance rate could be rather low compared to what it could be.
I've seen this work best on products that have a higher recurring fee.
Even with 99% off, you'll still need a really strong pitch to sell it... Yes, it's painful but still necessary in having to do the hard sell for 8 cents.
With your product having a pricing point of $5 or less, I suspect the "Try before you buy" model might suit you better. It'll end up costing you less as you won't have the merchant fees and you'll (fingers crossed) get more people to try with a lower barrier to entry. This also assumes your product is worth way more to the customer than the monthly asking price.