I understand your concerns because we've all started out in a similar situation. What to buy, where to shop, how much to spend, etc... One thing I do is ask how much something is. If it is out of my price range, I'll ask if they have something a little bit cheaper. If it is less than I can spend and I want something better, I'll ask if they have something a bit nicer. The retailer wants to make the sale and for you to be happy. I don't tell them how much I have to spend unless I trust them or their prices are in print.
Like you, I was overwhelmed when I buying my first Tahitian strand. Prices were pretty high buying an already made strand so I contacted a wholesaler (who doesn't sell anymore to individuals, sadly). I told him what I wanted and how much I wanted to spend. His prices were online and so it was easy to rearrange what I wanted, the sizes, and the number of pearls. It did take time and cooperation with the seller. I strung my pearls myself (first time doing this) and love my strand. I've replaced a few of the pearls in the strand over the years, but I have not really wanted another main T strand because I love mine so much. So I highly recommend getting a strand that you love. If not, you'll be spending more money on getting another strand in the future. And for the record, I have bought other T strands, just nothing to replace my main T strand. The others are different types of T strands (circles, tin cups, etc..).