in 3D many charge through per hour rate. You cant charge it through per-item modeled or through angle. But if the finishing required some simple shader and no-so high res modeling, then you can just charge in package like what soyabean86 suggested.

I got some time to spare,
so I'll explained how I do it....  (I used to do some freelance)
----------------------------

after discussion with the client and got all the necessary infos..

ask 50% before doing anything...

-----------------------

1st

start modeling, texturing.....etc.

interior for 1 area, for me took from scratch to final render & touch-up, about 2 days / or 1 whole day (if I don't sleep.. well.. I rarely sleep for days.)
for exterior 2-3 days.

render is really not a problem, with the right settings, for a high-resolution image the longest time it takes is around 1 hour.
I use 2 pc, 1 for render and other one for work (sometimes render when I'm not using it).
--------------------------

2nd give the client a preview

-for a preview I do a 6 angle camera shots,  brought into photoshop and combine all into 1 big image and email to them in jpg.
(no compositing in photoshop whatsoever.... just a normal low-res render.)

low-res render (1000 x 750) x 6 (camera shots) per area

---------------------

3rd  (estimated time, 1-2 days)

high-res version (5000 x 3750)  x 1  (selected angle from client) per area

usually at this stage I rendered the visual and do some touch-up & compositing in photoshop,
for example, an exterior render of a new shopping complex, in photoshop I put some real people, sky, cars, plants (landscaping)... etc.
skip unnecessary modeling for anything you can do in photoshop, those extra polygons = extra render time (and sometimes won't even render).

-------------------

4th

second preview. email them the final look (but low quality resolution)

when got an A-okay from the client,

next step :

done. ask the remaining payment before giving the final product.  (no money no talk.)
if not, do some correction/alteration... changing idea..? thats gonna cost extra.. (first changes is free)
-----------------
well.... different people, different way of doing stuff..

about the payment,
usually I gave them the base price for the service (modeling, compositing..etc) (not including render per piece, that's another price.)
I don't charge according to how many hours/days, and I rarely charge them base on complexity cause I always do my best even for a simple job.
(I hate doing a half-4ss job)
if they say.. "wahhliau weyyy... damn expensive mehh...?"
if that happens, most of the time, I just ask them what's their budget, and we go from there.
(you can always decline the work though.)
wahsaiii... long post already. 

anyway, good luck in your job.

.

Hi guys, thanks for all your sincere experienced suggestions and advices, been busy rushing the visuals for my client this few days till i don't have enough time to check my post. Actually he has given me a very tight schedule to finish my work and now I'm actually still rushing the visuals. I've send over a quotation for my client today, and I'm supposed to submit the FA to him this Friday. Anyway pls take a look at my quotation and tell me what you guys think....

Below is the visuals that he asked (numbers represents amount of printed visuals, different rooms and angels)

Living Room
1) Tv cabinet (single visual)
2) Partition (single visual)
3) Outdoor shoe rack( single visual)
4) Front view of living room from outside (through big window panels)
5) Inside view of living room towards Tv Cabinet and living room arch (extended balcony)
6) Inside view of living room towards partition and dining hall

Dining room
7) Dining room mirror (one panel)
8) Dining room mirror (three panel)

Resting area (beside dining room)
9) Front view from outside of resting area (pergola) looking towards dining room

Study Area (under staircase)
10) One visual showing study area

Dry kitchen
11) Dry kitchen 1st view
12) Dry kitchen 2nd view

Wet kitchen
13) One visual showing the whole wet kitchen

Study room (2nd floor)
14) One front view

Kid's Room (2nd floor)
15) Visual looking from outside to inside
16) Visual looking from inside towards wardrobe

Master Bedroom (3rd floor)
17) Visual focus on wedding photo area
18) Visual focus on bed

Walk-in Closet (3rd floor beside master bedroom)
19) One view focusing on wardrobe
20) One view focusing on cabinet/mirror

So i tell him:

3D visuals is normally charge by RM200- RM500 per room, and then sub-charge of different angle for a discount of 30%-50%. Or to make it easier is to simply charge RM300 per printed visual (some people charge by each printed visuals, the guy I know charge RM350 per piece). So base on the amount of visual he asked me to print, 20 visual x RM300 = RM6000

But i offer him a package price of RM500 per room(there are 10 rooms), with no limit of angles (he can take as many angle as he want) That way, 10 rooms x RM500 = RM5000.

How do you guys think?

Again, I'm new in this so if there's anything wrong, please don't scold me, haha... will gladly accept any suggestions and advice, thx....

hmmm... i dint really count la, but to be honest it doesn't take really long, cos it's all basic modeling lighting, cos that's how the client wants it, plain white blah blah blah...

not image la, base on the floorplan, blue print those type