For me, tea bags and blue foam went the way of the Dodo (no relation to the Go-Go;-)) with the emergence of really good (make that fantastic) cartomizers. My favorites are the 1.7-ml capacity, 1.6Ω
smok Tech dual
coils. Many suppliers carry them; I've gotten mine from
Hoosier* E-Cig Supply and
Vapor Junction. In each case, $2 a piece (although VJ's are sold in $10 five-packs). [It may be an anomaly, but my eGo cone fits over Vapor Junction dual coils (tightly), whereas the one I received from Hoosier does not (until I peeled off the black covering).]
* FYI: I'm pretty sure that my fellow veteran, Hoosier, has no connection with the supplier of that name ... other than residing in the same state.

The dual coils work great on the eGo, although you will see official warnings against using any atomizer or cartomizer with a resistance lower than 2.0Ω on a fat batt like the eGo (because of potential damage to the switch mosfet) ... and these never should be used on a low mAh battery like the 510. [Nothing dangerous; just the possibility of shortening the life of your battery.] A very popular alternative (which I haven't tried) is the shorter 1-ml capacity Boge 2.0Ω cartomizer also carried by many suppliers, e.g.,
MadVapes for $9 per five-pack.
If you want an entirely new e-cig (i.e., atty/carto
and battery kit) for far less than $100, you may want to consider the 750 mAh
Riva-510 (or
Riva-901 for your wife) from Liberty-Flights for $30. It is the "Lite Bundle", but there is nothing lite about it: these are full two-battery, two-atomizer kits. [Be sure to click on the "20% Discount" icon in the upper left of the screen first in order to see this low price.] In the case of the Riva-510, for $5 more, you could get the "Special Edition" which is 3.7V (rather than the 3.2V of the standard Riva or your current eGo) and includes slightly lower resistance atomizers. This would provide a more intense vaping experience, but is not really necessary with an LR cartomizer like the dual coil.
For a 3.7V fat batt with even higher mAh (and greater length), BreezEsmokes sells the 510/eGo-compatible
1100 mAh KGO (in black) for $43. [I got mine in chrome from
Hoosier E-Cig Supply, but they currently are out of stock.] Your wife might prefer the 901/Kr8-compatible, automatic-battery
1300 mAh Echo (also 3.7V) from Cool Vapes for $60, which
I recently reviewed.
This weekend, I wrote about several of these PVs and cartomizers in this post:
http://www.e-cigarette-forum.com/fo...-dripper-discovers-cartos-3-7v-fat-batts.html.