I'm considering building a bass this winter and am planning on making a fretless four string and I'm trying to get a warm mellow tone, one that is very similar to an upright.
1)What neck style would work best for the sound I want and what style is easiest to build?
2)what type of wood do you recommend i use?
3)How much should i plan on spending? I'd like this to be a nice bass but would like to spend under $1500

T.I.A

if you spend half of your budget, you have probably wasted some money somewhere

That amount is assuming that I've got to buy a few tools, I'm pretty sure I've got everything I need but the garage is still a mess from a grad party a few weeks ago so no telling what all is out there.
How much should I expect to spend on materials?

I'm considering building a bass this winter and am planning on making a fretless four string and I'm trying to get a warm mellow tone, one that is very similar to an upright.
1)What neck style would work best for the sound I want and what style is easiest to build?
2)what type of wood do you recommend i use?
3)How much should i plan on spending? I'd like this to be a nice bass but would like to spend under $1500

T.I.A

1. I am not sure what you mean by this exactly, I thought you might be asking what types of wood to use but you did that in your second question.
2. If you're starting out, stick to the basics, stuff thats inexpensive, and readily available. Maple, ash, walnut. mahogany, etc etc. If you want to do something more exotic, by all means go for it. I did on my first bass.
3. I think this is a very reasonable budget. Youll probably spend about half or a little less on wood and parts. What do you have for tools already?

I meant in the terms of bolt on, set, and through necks. I have all the basic garage tools(table saw miter saw etc.) grinders, and it's possible that i have a router some where out there.

I'd probably do a bolt on neck for your first time, in case something goes wonky with either the body or neck, you don't have to re-make both, or try to disassemble something that has already been glued up.

If you are wanting an upright tone, glued in might be a little better, but the difficulty level might be such that you'd still want to try bolt on first.

Personally, to get an upright sound, I'd probably go longer scale (36" - 38"), and I'd incorporate a piezo pickup or contact pickup of some kind, and blend it with an electric pickup using an active preamp. That's just me though.

Short scale basses can give you a bit of that sound... take the Rob Allen Mouse 30 basses - big on acoustic tone, with only 30" scale length... that combined with the tape-wound strings give it a lot of punch, but not so much sustain.

Spend about $50-75 on books, the Nelvin Hiscock one would be a good start.

I agree with all of the advice given previously.

My personal thought would be to go with maple or walnut for the neck, and walnut or mahogany for the body with a rosewood or ebony fingerboard. I had a mahogany body/neck bass with a ebony board (fretless) and I was able to make a great upright tone.

if you really want that upright sound, you could always build a chambered body and utilize one of these necks

http://www.urbbob.com/bassneck.html

These would then be handy accessories to complete the job

http://www.urbbob.com/fingerboards.html#ebony
http://www.urbbob.com/tuningmachines.html
http://www.urbbob.com/tailpieces.html#composite
http://www.urbbob.com/adjbridge.html
http://www.urbbob.com/endpins.html
http://www.urbbob.com/pickuppackages.html

all the best,

R