What brand camera are you using. I mention this because if 1. finances are tight and 2. you are using Canon gear; you could pick up a used Canon 420EX flash at Adorama or B&H in New York City for around $50.00 or so. This is an older flash but will work very well in TTL mode with any Canon DSLR. It doesn't have manual capability but, if you add a diffuser/reflector along the lines of a Joe Demb Flash Diffuser Pro, you should be able to get decent imagery.
www.dembflashproducts.com
I am pretty certain that either Adorama or B&H would have a less expensive diffuser/reflector that will work. There was a time when eBay was flooded with Chinese knock offs of the Joe Demb Flash Diffuser Pro. I don't see them anymore. This unit might do the job for you...
https://www.ebay.com/itm/Speedlight-...QAAOSwGhFZiA0i
I have many flash units but purchased an extra 420EX within the past year so I have two of them. I like these units because they are relatively small, have High Speed Sync capability and are quite reliable. I often carry one or two of these on every shoot I go on.
If you don't shoot Canon or if your budget isn't bare bones. I would tend to look at a more expensive flash. For your use, I would definitely want through the lens metering but, would accept a third party flash such as one of the Flashpoint units sold by Adorama these are Godox flashes that have been rebranded. Yongnuo also has a decent flash line...
If I were setting up for the kind of job you are anticipating, I would equip myself with the following:
1. A TTL capable flash unit (with extra batteries)
2. A Joe Demb Flash Diffuser Professional
3. An off camera sync cord
4. A Stroboframe Camera Flip Bracket
https://www.ebay.com/itm/Stroboframe...QAAOSwdd9achtP
This flash bracket will keep the flash unit over your lens. The camera flip will allow you to keep the flash in bounce mode without having to change the orientation of the flash when you switch from horizontal to vertical shooting...
I like the Stroboframe bracket with a solid top bar as referred to in the eBay posting above because I like to use this bar as a carry handle when not actually shooting.
The hotshoe flash on a Stroboframe Camera Flip Bracket modified with the Joe Demb Flash Diffuser will give decent lighting...
This shot was done at twilight outside without a ceiling off which to bounce the flash. I tilted the bounce card 45 degrees forward to direct the flash towards my subject. However, the light is still fairly soft and pleasing.
The hair light came from the setting sun...