I can't speak for the prices on your server, but a decent way to boost iLv. as stated already - was the lv. 49 accessories - but if they are cheap on your server, you may also want to look into the HQ ilv. 55 acessories (Imperial Operative Wristlets and the like) On my server, for example - the HQ is around 8-12 K usually - and many people used it for cheap spiritbonding. Once you finish the story, you can do Castrum Meridium or Praetorium - and make sure you use your duty roulette for the story etc as well - to quickly build Philosophy tomes, then buy the Darklight set off Rowena's helpers (Revnant's Toll, x22, y6). A full set will run you somewhere around 5-5.5K philosophy tomes, but if you run your roulette daily on your 50 class, you'll make it rather faster then you would think - [300 bonus tomes each day if you do the low level roulette on your 50 [100 philo, 10 mytho] and the Story Roulette [200 Philo] means that from one Castrum or Prae, and one lower level dungeon, you have enough to purchase one of your darklight accessories [Waist, neck, ear, wrist, ring - 375 philosophy each]. Do one more run, and you can get your bard darklight head, hands or feet [495 philosophy each] then the big ones to save for are the legs and body, each costing 825 philosophy each.
If you are able to, I'd recommend the following strategy:
Purchase the accessories off the Market Board (MB, AH abbreviated, you'll see it either way) for gil to get you started. Once you have those - and you want the DEX gear accessories, not the VIT ones like you are using for your ring and wrist - start farming Duty Roulette (low dungeon) on your 50, and the Story Mission roulette once each day, then just farming Castrum Meridium continuously for your first few armor pieces - the head, feet, and hands. Once you have those, you should usually be geared okay enough to do things like Amdapoor or Wanderer's palace normal runs, along with Ifrit. If not, farm a few more times and get your waist accessory - as you always want to gear the Left side first (Armor), then the right (accessories) side. You want to then farm ifrit to get his bow - depending on your luck it might take a little bit, but it is worth it. While farming ifrit for bow, keep doing the other dungeons for the Philiosophy stones to buy your body and legs along with your accessories.