There really isn't much to buy from NPC's in FFXIV as far as gear and weapons go it is very heavily crafter dependant. You can however get R1 weapons for every class from all the various shops. Hawkers Alley in Lower Limsa has a fair few NPC stalls. As for the Market Wards they are entered in Upper Limsa where it says "Southern Islands". Though not sure if you will find anything there, not sure what it's like on Besaid but on Lindblum there is a distinct lack of lower level gear ever available.
The best place to go shopping is Ul'dah's Market Ward's so take the ferry from LL over to the otherside and you can run to Ul'dah in relative safety. Make sure you touch every crystal you pass to unlock them for anima teleports and don't forget the ones in the cities you visit.
If I was you I would stick to the R1 starting gear and level all my jobs up to R10, it doesn't take long as you probably know by levelling MRD. Once they are all 10 then start trying to buy R15-20 gear you level up so fast there is not much point in buying R10 gear. If you need gill then do as best you can to get to R13 to unlock R20 Leves at Camp Bloodshore. Once you start doing those the gill starts flying in and if you spend wisely you will never be short again.
Hope that helps a bit ^^