Finally, my time to shine. I struggled with this around ~6 months ago. I would definitely get something that is viable in the longer term. My suit for interviews has already paid off. On top of wearing it for interviews, I am now also getting to use it for my wedding! Excuse my language. Do you want to waste your money on a piece of ****? Probably not. If you get a decent suit, it will last you a decade minimum, longer if you take care of it. And, given that you usually wear suits for making first impressions, you do not want to just put 0 effort in. That can affect how you present yourself while wearing the suit in the future. If you don't put effort into getting a good suit, you'll probably be getting a new one and spending more money in the future. With that said, you don't need to spend a lot to get a quality suit. How much you want to spend will determine where you get your suit from.
<$200
Ok, so your budget isn't much to work with. That is fine. With a budget this small, though, you aren't going to get something retail. Hit up the thrift stores because you're not about to spend $50 on a t-shirt. That is just some ignorant---. Alright, so you see a suit. Next, the key to a good-looking suit is fit. That is most important. Does the suit fit? Out of a thrift store, it probably will not but that's ok. Find one that is close to size.
Do not find one that is undersized. If you find one you like and it's a little big, that's perfect. You want more fabric to work with, not less.
Try to ensure the length and shoulders of the suit fit; these are the most costly adjustments that a tailor can fix. Adjusting the shoulders can sometimes cost as much as the suit itself. Find a decent tailor. Whether you know one or you have to use reviews on the internet, make sure it's someone who knows what they're doing. When you visit them, say you want your suit fitte. They should ask you questions about how you want it to look. Hopefully, they will be placing pins in your suit (while you wear it) as you tell them how you want it to fit. I recommend especially taking your suit jacket and pants to tailors if you buy from thrift stores. The shirt you can get away with being loose-ish if it is under a jacket. The more fitted your suit, the more professional and put-together you look. If you plan on not wearing the jacket a lot, you may as well get the shirt tailored as well. It can only help in the future. Remember, even if cost is an issue, this is a long-term investment. This is not a t-shirt or pair of sweatpants that you will be getting rid of in the next five years. I cannot say too much about brands as the manufacturing year of suits means the quality of specific brands will vary. With that said, you generally want to see where a suit was made. Many thrift stores have custom-made suits from private tailors as well as brand-name suits. Honestly, it's a fantastic place if you vet what you buy. You can get $1000-$2000 suits at thrift stores for <$100. You should feel the material. You'll likely want a wool suit for a standard piece. The wool used in suits should not feel scratchy but smooth in a non-silky way. I would absolutely recommend staying away from polyester/rayon. These materials do not feel good, are cheap, and have a shine to them. Once you try on the suits of different materials, you will tell the difference. I got my first suit ever from a thrift store for $8. I spent less than $80 on tailoring. It is fitted and looks great. I still have it and use it on occasion. Since it is black, I opted to get a navy suit for my interview season. While I doubt this really mattered for interview season specifically, I wanted to have a navy suit for the future as well.
Note: private tailoring can take up to a month depending on how popular the tailor is.
~$200
If you know your measurements,
these tailors on eBay.
JCP suits fall here. I personally like the thrift store option better as the quality and construction is much better if you find the right suit. If you do buy from JCP, just make sure that you know your measurements beforehand since the salesmen measure wrong. Again, the idea of wool > poly-blend is a good rule of thumb here.
~$400
Suitsupply.com. At this price, you will be looking at their blue line. Despite the name, the suits are varying colors. Expect to spend slightly upwards of $400 unless you fit their off-the-rack suits very well. I personally got my suit (Napoli Navy) from one of their physical stores and had it tailored by them (their in-store staff measure properly) on-site for $40. They tailored my suit within a day of purchase. The suits here are comparable in construction/quality to $800-$900 suits elsewhere. You honestly can't go wrong with Suitsupply.
Others may recommend Indochino. I have heard bad things about their QC on their suits with measurements being off, seams not properly sewn, etc. so I can only tell you that is why I have not recommended them at this price point.
>$500
You can find a decent suit at this price point just about anywhere as long as you know what you're doing. Do research and make sure you check the quality/construction. At this price-point, tailors are also a great option when considering buying a suit. They usually custom-make the suits specific to your measurements. You may have to shop around for tailors depending on your budget. Name-brand and designer suits are also available at this price point. Prepare to have the suit tailored, though, unless you get lucky with an off-the-rack item.