The premium outlets are very close, from POR we had a rental car and turned left out of POR and followed signs to I-4 towards Orlando. Once you get on I-4, it's the first exit. Go straight at the end of the exit, you'll pass a sign that says Little Lake Bryan. The road will bend a few times and put you right to the outlets. I would think it wouldn't cost more than $15 or so each way in a taxi.
You may be able to save a few more bucks if you took a cab from Downtown Disney, as it appears closer to the outlets.
Can't help you with any info on the lynx buses.