Not gonna give a 70+ shopping list here (hence I will be saying "till 70" in some cases, though some of them last higher). At that point you're high enough to a. make money and b. make your own decisions on what to get.
Weapon: If money's not an option, sell that Monster Signa of yours to fund other stuff, it's not worth its price tag. Consider a
Ceremonial Dagger (which you can even farm, if need be, the mobs that drop it are quite wimpy) for the +10 MP, until 40 when you can use the
Paper Knife +
Elegant Shield combo for +3 CHR and +6 MP on a budget. At 48 you can replace the Paper Knife with a
Shellbuster for 2 more CHR.
Level 51 onward, use
Light Staff for Cure/Curaga, Lullaby, Requiem, Finale, and Dark Threnody. Use
Earth Staff for Elegy and Lightning Threnody. (Also macro it into any buffs you use, in case you get hit with a stray aoe in the meantime. Staves do not affect buffs positively or negatively.) And use
Dark Staff for resting MP and for Light Threnody. For the rest of your threnodies, you can either wear Light/Dark Staff (for the +1 CHR) or stick with that Shellbuster/Elegant Shield combo.
Instruments (Mary's Horn will be somewhat pricy, rest are all fairly reasonable):
Important ones for exp are:
Cornette +1 (Minuet +2, level 4)
Piccolo +1 (Threnody +2, level 9)
Mary's Horn (Lullaby +1, level 14)
Traversiere +1 (Madrigal +2, level 32)
Faerie Piccolo (March +2, level 36; not used much at lower levels)
Rose Harp +1 (Etude +2, level 36; not used much at higher levels)
Horn +1 (Elegy +2, level 40)
Angel's Flute +1 (Prelude +2, level 48; its use is limited pretty much to RNG and COR)
Nursemaid's Harp (Lullaby +2, level 60; better potential but less reliability than Mary's Horn)
Sorrowful Harp (Threnody +3, level 70; better potential but less reliability than Piccolo +1)
Nice things to have for other purposes, but which won't matter much for exp:
Gemshorn +1 (Mambo +2, level 19)
Siren Flute (Requiem +2, level 23)
Crumhorn +1 (Carol +2, level 56)
Ebony Harp +1 (Paeon +2, level 60)
Everything else is either useless (or so rarely useful as to not matter, such as the Minne instrument) or a luxury item.
Head: Your Noble's Ribbon, debuff-wise, will last you until a quested
Opo-opo Crown at 65. If you're not having trouble with debuffs, consider the series of MP hairpins:
Silver Hairpin (level 20, MP +15)
Electrum Hairpin (level 40, MP +25)
Gold Hairpin (level 50, MP +30)
(AF head is mostly useless.)
Neck: Your Bird Whistle will last you until
Star Necklace at 59. Whether you get or skip the Star Necklace (you'd have to quest it), use
Wind Torque and
String Torque (macro appropriately) starting at 65. Wind Torque is expensive but very much worth it.
Earrings: On a budget, skip the level 35 skill earrings (
Singing Earring,
String Earring, and
Wind Earring). They're among the best earrings a bard can wear, mind you, but they have quite a price tag (well, string is affordable, but isn't so useful). They're more endgame purchases that you can then use while level-capped. Or things that rich people can buy if levelling bard as a second job.
More practical: use various MP earrings until 52, at which point use a pair of NQ
Melody Earrings for 1 CHR each. (Upgrading to HQ isn't worth the money since you're on a budget, and arguably isn't worth the money period.)
Body: Your Custom Tunic can last you until AF if you want (since
Gaudy Harness is out of the picture for you). However, you may prefer to wear something with slightly higher defense in the meantime, since the 1 CHR on RSE body is easily sacrificed. Perhaps a
Royal Squire's Robe at 40, for better defense along with +10 MP.
At 58, you can upgrade to the AF body,
Choral Justaucorps. It has decent defense and a bit of +VIT and -enmity, and it boosts your string skill a bit. At 62, if you want to camp it, you can go for a
Minstrel's Coat, which is a good upgrade but one you may not want to go out of your way to get. Either way, you're fine wearing either of those to 70.
(Keep in mind that there are other benefits to doing CoP too, so you may want to take a bit of time off from level grinding and money/equip grinding and spend a bit of time on missions, even if you don't get a Gaudy Harness out of it.)
Hands: You didn't say what you were currently using here. I'd suggest
Devotee's Mitts until AF hands, the
Choral Cuffs, which you can wear till 70.
Rings: If you need CHR, use the latest NQ CHR rings (
Pearl Ring is CHR +2, level 36;
Moon Ring is CHR +3, level 54). If you need MP,
Electrum Rings are very cheap and nicely effective at level 40+. If you weren't on a budget, I'd also sing the praises of the
Minstrel's Ring, however it has quite a price tag.
Back: At 44 you can wear an
Aurora Mantle for +10 MP. At 54, get the
Jester's Cape +1 for +10 CHR. I normally suggest NQs, but this HQ is reasonably priced and you'll be using it forever, so get HQ in this case.
Waist: Upgrade to
Corsette +1 at 40, and then
Gleeman's Belt at 60. Both have +6 CHR, but Gleeman's Belt is a. cheaper and b. has better other stats, though the other stats in either case won't matter much for exp.
Legs: Your Custom Slacks are wonderful godly things (32 MP, 1 CHR, yum) and they'll last you right on up to AF legs,
Choral Cannions, at level 56, which will last you until 70. Even then, you may want to hang on to the RSE if you need MP.
Feet: Your RSE feet,
Custom M Boots are a better choice than your current Mage's Sandals. And there's not really much of anything better to wear in the foot slot until after 70, since AF feet are rather meh.
Well,
Mannequin Pumps are good, but you need both to have quested yourself a mannequin, and to have gotten yourself Tavnazia access, for that. And I doubt you've done the first and I know you haven't done the second. If you can stand losing the 12 MP, though, you may want to keep an eye out for stuff with more defense. /shrug
Food: pies for max MP or cookies for hMP, some cheap defense food like fishkabob or boiled crab if you're pulling (or even just getting hit by a lot of aoes), and at 65+, if you're wearing an Opo-opo Crown, you'd better keep up a diet of eternally misspelled
Pamamas, or else the crown will have a *negative* effect on you.