Running electrical wire through plaster and lath?

[Ryan Short]

Hi everyone on BP, I recently closed a 4 family house in Massachusetts in June. The house has a 1BDRM, 2BDRM, 3BDRM, and a 4BDRM. The 1 BDRM and the 2 BDRM are rented from before and are close to paying for the mortgage. I have been renovating the 2 other units the past month and have gotten a lot done. I have been researching as much as possible about running electrical wire and adding lights and outlets. I'm just starting out and I'm only 23 so I don't have a lot of reserves but I do have some credit available. I got a estimate from a friend of a friends electrician, and he came in at $2400 for adding 10-15 outlets, 4 or 5 lights, and adding 3 or 4 circuits. I can't really afford to pay that but will if I have to. I was wondering what's the best and easiest way to run electrical wires through plaster and laths. I could run some off old circuits but I'm going to have to add a couple new circuits no matter what. I was thinking about doing what I can then have him come back and give a new estimate. I also would like to cut the smallest amount of walls possible, for repair reasons. I found a way to run the wires up to the 2nd and 3rd floor but not sure what to do when I run into old plaster. Also this is an older home that has some electrical conduit in one or two rooms. So that is an option but most of the units is getting renovated, just don't want to outdate anything if I don't have to. Thank you in advance for giving any advice!