Disclaimer: Actual bells and whistles not included.
##Recommendations:
Mods
Primed Flow
350 Đ + 110,000 Cr
+275% max energy for frames. Lets you cast more abilities, and helps smooth out the rhapsodic rhythm of energy drops during the mission. Also great for Quick Thinking builds. Unless you never use caster frames, get this. (Although, you could use Archon Flow instead. That one's bonus isn't worth the extra costs, though.)
Primed Point Blank
300 Đ + 110,000 Cr
+165% Damage for Shotguns. Boosting base damage is essential in every mod setup. This mod does just that. It's a must have for most shotguns, although it can be circumvented with frame-based buffs (i. e. Vex Armor) , Galvanized Savvy (for high-RoF status shotties) , or primary arcanes.
Buzz Kill
375 Đ + 150,000 Cr
+120% Slash damage for Melee. Might have some use in fringe builds, but don't spend ducats on it. Get it from Eidolon hunts or buy if for a few plat.
Primed Heavy Trauma
350 Đ + 100,000 Cr
+165% Impact damage for Melee. If you want to create the perfect Atlas statstick, this mod is good. Otherwise, it's safe to skip. (It could also work with Baruuk's ult, but Reactive Storm is better, and overrides PHT's bonus.)
Weapons
Baro's weapons typically fall into low A or B rank in tierlists, so DE at least tries to justify their asking price. And even the trashiest of weapons are worth buying if you need the Mastery Rank they provide. Or if you have good riven for them, since their disposition is usually quite high. On the other hand, Warframe has a massive arsenal, and for every weapon Baro sells, there's gonna be another that can do the same job just as well, or even better. In that sense, everything in here is safe to skip.
Ignis Wraith
550 Đ + 250,000 Cr
An excellent spray-and-slay flamethrower, perfect for low-level mobbing and can hold itself at surprisingly high levels. That said, you shouldn't spend ducats on it: the BP is also available from Clan Research (assuming your Clan is level 10). You can also farm the BP from Railjack.
Vericres
410 Đ + 200,000 Cr
This is very middle-of-the-road warfan. I'd suggest investing into any other member of its category - the Gunsen Prime, the Quassus or the Arum Spinosa instead, which have better stats and in the latter two's case, throw special projectiles on heavy attacks.
Cosmetics
The Stranger's Hood
550 Đ + 500,000 Cr
New! An Operator cosmetic that was originally a promotional drop for Duviri. While the description says Operator, it is also equippable on the Drifter, as far as I can tell. Unfortunately, it still makes you look like a little kid wearing their granma's headscarf.
Prisma Latron Armor Set
900 Đ + 595,000 Cr
A curvy armor set, with swirling Prisma looks. Note that the shoulder plate can only go on the left shoulder.
Prisma Naberus
220 Đ + 140,000 Cr
Shark fin floaties for your shoulders.
Prisma Hecate Syandana
250 Đ + 300,000 Cr
A small, elegant, minimalistic Syandana.
Dual Sword Lemnas Skin
350 Đ + 300,000 Cr
If you like your dual swords to look like very impractical icepicks, this one is for you.
Ki'Teer Cornu Diadem
525 Đ + 375,000 Cr
In the earliest form of the legend, unicorns were fierce and combative creatures, and the virgin's touch were the only thing that could quell the savagery of the beasts. Acquire this diadem if you want to embody the spirit of those primeval unicorns. Or if you just want to look ridiculous.
Nexus Gene-Masking Kit
200 Đ + 300,000 Cr
Gives a fur pattern and coloring options to Kavats. The base Kavat Gene Masking Kit and the Moonless skin already gives a decent set of fur colors, but more options are always nice. (These options are all ""neon shades of purple"" , though.)
Exo-Sac Archwing Skin
400 Đ + 300,000 Cr
A bulky Orokin-ish skin for Archwings. AW skins weren't really a thing until now, so if you want your Itzal or Elytron to match your Prime gear, this is a good buy.
Noggle Statue - Erra
75 Đ + 300,000 Cr
Bobblehead of our incel space uncle.
Bronze Kubrow Bust
220 Đ + 250,000 Cr
A bronze statue of your pet's head. Just be aware, at its default size, it's really small, and even scaled up to max, it's barely life-sized.
Deimos Kymaeros Prex
75 Đ + 100,000 Cr
Prex cards depicting a Deimos-associated entity. These were given away like candy during the Heart of Deimos update. If you haven't got them then, you can get them now for a modest price.
Prisma Lotus Sigil
55 Đ + 45,000 Cr
An elaborate symbol of the Lotus, in monochrome.
Prisma Kavat Glyph
80 Đ + 50,000 Cr
Your pet represented in an abstract triangular artstyle.
One the older step-Ephemeras, and rather insubstantial compared to, say, Eros Wings or Vengeful Charge. A permanent fixture of Baro's repertoire.
I might have sharp and opinionated remarks about these items, but I'm not the fashion police. Buy whatever cosmetic tickles your fancy!
Other
3 Day Credit Booster
350 Đ + 75,000 Cr
The same booster you get from the Market or Sortie rewards. They don't stack with them by having their effects multiplied - only by having their duration added. It's typically better to sell your Prime parts for plat and buy the booster directly from the market.
If you haven't played Sands of Inaros yet, buy the quest key and do it (and bring your best setup for scanning Kavats). If you have Inaros Prime, you can buy the Baro Void-Signal (one per visit) to access some special cosmetics.
Also, check the answers below for second opinions.