How to make an assessment of the potential cost / terms of the project when ordering from freelancers?

Question

Project management

Good day!
This is a new question for me, I have never done this kind of research before. I'm sure a lot of people do this several times a day, so I'm looking for your advice.
In a nutshell, the question can be formulated as follows: how to estimate the time and cost of the project, where to get reliable data on the cost of watches, etc.
If more words: There have already been attempts to directly request dates and prices, through personal contacts with people, the path turned out to be very inefficient, in terms of time, because. each time, a potential performer asks for time to study / evaluate in order to understand the description, look at the old code, etc. Moreover, different people give noticeably different terms and prices.
The main point is that there is a budget and you need to get a functioning project in 2 months, if something (feature / functionality) does not fit into the budget or can potentially increase the time and this is not vital, it will be removed from the task, but in order to do it and play around with the complexity of the features and their priority, you need to somehow magically have a quick answer to the question "how do the terms and prices change if we remove / simplify this, but add this?", re-request every time - long and wastes people's time. Therefore, I am looking for an answer to the question: how to organize this process correctly.
Thank you in advance if you poke at resources or methods, etc.

Answer 1

It is necessary to write a clear and unambiguous TOR.
It is desirable that a technically competent person who has taken part in previous projects writes. So that based on my experience I could at least roughly estimate. If you don't have such experience, hire a PM or a team leader you trust.
Well, yes, it's always like that. An experienced person will do complex work several times faster than a beginner, but his conditional hour of work will cost more.
Then take only experienced ones. But still, no one is immune from the disruption of deadlines. It is better to put into the project 2-3 times more time than the contractor calls

Answer 2

Short - fast and cheap - no way.
If you ask different people to run a marathon, people will name different times and different costs. In reality, there is no "correct" estimate of time and budget.
Or another example. A much simpler product compared to (almost) any IT project is bread, which is mass-produced and mankind has a thousand-year experience of its creation, if not more. So 1) the same bread in different stores costs differently 2) there are dozens of all kinds of bread in the store 3) different people will agree to make it for different money and terms.
There are no magic methods. Your task requires a lot of work anyway. Creating a Terms of Reference and evaluating it, especially for each feature, is a lot of work for a highly qualified and experienced (and therefore expensive) specialist.
one. Decide who you will work with. This should not depend much on money (including because you don’t have grades yet), but more on how much you trust each other, how well you work together, and you feel comfortable working together. (Lack of trust or incompatibility of working methods is too big a risk of project failure, for example, we don’t even take on such projects).
2 . Sit down with the implementers or their representative and break the project into features, you can be pretty rough. Those. Make a numbered list of all features. In excel or google spreadsheets.
3. The performer will evaluate them, put down their marks in adjacent columns. Estimates will also be quite rough. Let's talk about money and timing. Those. you give this list to the team of the performer, the team evaluates. This may take hours or days (for a 2 month project). It is clear that features can be interconnected, estimates too, etc. We keep this in mind (in obvious cases) or make notes about dependencies next to the column (in non-obvious ones).
4 . After that, you look at the scores and decide what to do and what not.
5 . With those features that you decide to leave, you work in more detail. You write a more detailed specification, checks are made, estimates are adjusted, the work plan is refined again, etc.
That's about it. This is a general principle. Those. first, you estimate roughly so as not to waste time, then you evaluate those features that fit into the budget and deadlines more accurately. This saves time and money. You were advised to write as accurate a specification as possible right away - this is not the most effective option. You will spend time thinking in detail and describing what will not be included in the project.
If you have never done this, there will be many pitfalls, large and small, serious and not so serious fakups. But this cannot be learned on the Toaster or in books, only experience.
Then you will start to make a project, and something will not go according to plan, so you will need to work with Changes in the Project and adjust the work plan along the way. But that's a slightly different story.

Answer 3

Firstly, the evaluation of a large project is a long and complex process, as it requires deep immersion, another feature of the evaluation is not accurate.
So quickly, simply and for free, no one will more or less accurately evaluate the project