Zakum Helmets are relatively cheap to purchase (for the stats they give). Most guilds sell for around 30-40mil for 1 run, but with the helm you get roughly +15 to all stats, 20 acc, 20 avoid, 150 def/mdef.
Dex capes can be relatively cheap to self scroll. Wait until the next 'gach box' event rolls around, PACs will be cheap during this. Grab a 2 att pac or so, and try to 30% dex it once. Once you get a 30% to pass, 60% it the rest of the way (unless you are feeling bold, then try another 30).
Dex earrings are EXPENSIVE! Look for good deals in the FM on dex scrolls, and attempt to self scroll. Again, use the 30% method, get a 30 to work, then finish off with 70%s. (60%s for earring for dex are insanely expensive, dont bother unless 3 or moree 30%s have worked).
Dex shoes can be simply self-scrolled. Tons of quests give you Scrolls for Shoes for Jump. Just grab some snow-shoes for your class, and again, get a 30 passed, and finish with 60%s. By the time you hit lvl 70, you will have a TON of shoes for jump scrolls. (if you save em and dont sell them)
Dex overalls can be the most expensive of all equips. To start, just 100% a bathrobe for dex (+10 dex). Use this until you have enough meso to purchase a 20+ dex o/a.
Also, more important than ANY of these equips is getting a decent attack work glove. You COULD choose to self-scroll, but I reccomend against it (unless you are rich). Look through the fm, and try to grab at least a 6 att wg to start. After you earn more meso, (and by lvl 85 or so), be sure to get a 10+ att.
Another Dex equip you can purchase is a Dep Star (although with the insane new BigFoot and new PQ pendant, these may become quite expensive).
If you are swimming in money, scroll a face accessory for Dex. The boost will be minimal at best, but it all adds up.
As for making the meso, there's a nice 'get rich' thread by lexy. Idk if it would work for everyone, but it should be a great start.
All this added up (using Kradian prices, that's what I know, and I assume deme is close to it)
Zhelm: 35mil
20+ Overall Dex: 40mil
5-10 Dex Shoes:10-50mil
5-10 Dex 1-2Att pac:10-70mil
5-10 Dex Earrings: 15-70mil
Dep Star: 40-50mil
1-3 dex Face Accessory:50+mil
6-10att WGS: 6-50mil.
As you can see, even a few extra stats on an item REALLY raise its price, but those extra stats also add up fast. If you took a cheaper route and purchased only the minimal amount of dex equips, you would have roughly 40-50 added dex. However, if you spent the full price, and bought some better equips, your added dex would be 65-75. If you REALLY spent a ton of meso and scrolled a zhelm for at least 30 dex, you can put yourself around +100 total dex.
I've been through the same thing trying to stay low-dex as a Night Lord. It is expensive, and your damage may not be rewarded right away, but in the long run, you will have better damage.